B1 · Mittelstufe Kapitel 31

Possibility and Probability

5 Gesamtregeln
51 Beispiele
6 Min.
Regeln in diesem Kapitel Schnelle Übung

Chapter in 30 Seconds

Master the art of expressing uncertainty and logical deductions with professional precision.

  • Differentiate between weak and strong possibilities using modal verbs.
  • Make logical deductions based on evidence using 'must' and 'can't'.
  • Use advanced probability adjectives and adverbs to sound more natural.
Stop guessing, start expressing levels of certainty.

Was du lernen wirst

Ever wonder how likely something is? This chapter helps you confidently discuss possibilities with may and might, and make logical deductions using must, so you can express yourself more precisely and naturally.

Learning Objectives

By the end of this chapter, you will be able to:

  1. 1
    By the end you will be able to: describe a 30-50% chance of an event happening using may or might.
  2. 2
    By the end you will be able to: conclude that something is definitely true or false based on evidence.
  3. 3
    By the end you will be able to: rank different outcomes from 'unlikely' to 'bound to' using non-modal structures.

Kapitel-Leitfaden

Overview

As a B1 English learner, you're moving beyond basic communication and starting to express more nuanced ideas. This is where understanding English possibility and probability becomes incredibly useful! Imagine you're making plans, discussing news, or even just wondering about the weather – knowing how to express how likely something is can really boost your confidence and make your English sound much more natural.
This chapter will equip you with essential tools to talk about uncertainty and make logical deductions.
We'll explore how to use modal verbs like may and might to express things that are simply possible, and how must helps you sound confident about a logical conclusion. You'll also learn handy phrases like may well and might well to express a higher degree of probability. By mastering these concepts, you'll be able to discuss potential outcomes, explain why you think something is true, and even confidently state when something just can't be!
These are all key skills for navigating a wide range of everyday conversations at the B1 English grammar level.
Being able to differentiate between something that *might* happen and something that *must* be true based on evidence will help you communicate more precisely. It's about adding depth to your English, allowing you to share your thoughts and reasoning in a clear and convincing way. Get ready to discuss possibilities and probabilities like a pro!

How This Grammar Works

Let's break down the core grammar rules for expressing possibility and probability in English. We use modal verbs to do this, and they always precede a base verb (the infinitive without 'to').
When you're talking about something that is possible, but not certain, you'll use may or might. They are largely interchangeable for present or future possibility. For example,
It may rain later
means there's a chance of rain.
Similarly,
She might be at the library
suggests it's a possibility, but you're not sure. These express general uncertainty or a 'maybe' situation.
Now, if you're quite sure about something based on evidence or logic, you use must. This isn't about obligation; it's about making a logical deduction. If your friend has been studying all night, you could say,
She must be tired.
You're almost certain based on the clues.
This is called the epistemic must. The evidence makes it highly probable.
To add a bit more strength to your predictions, you can use may well or might well. These phrases indicate that something is quite likely because it makes good sense or there are strong reasons for it. For instance, "If he doesn't study, he may well fail the exam" implies that it's a very probable outcome given his actions.
It's stronger than just may or might alone, suggesting a reasonable expectation.
Finally, when you're absolutely certain that something is logically impossible, you use can't. For example, if you see someone enter a room and then immediately leave through the same door, you could say, "She can't be in the room anymore." The evidence tells you it's impossible. It's the opposite of must for logical deduction.
These structures build on each other, allowing you to express varying degrees of certainty.

Common Mistakes

  1. 1✗ Using 'must' for permission instead of logical deduction in this context.
✓ He must be home, his car is in the driveway. (Correct: Logical deduction)
✗ You must go to the party. (Incorrect for probability; this is obligation. For possibility, you might say
You might go to the party if you want.
)
*Explanation:* Remember that the 'must' we're focusing on here is for making a logical guess, not for giving orders or saying something is required.
  1. 1✗ Confusing 'may' and 'might' for past possibility.
✓ She may have forgotten her keys. (Correct for past possibility)
✗ She might forget her keys yesterday. (Incorrect: 'Might' for past possibility needs 'have' + past participle)
*Explanation:* For past possibility or probability, you need to use may have + past participle or might have + past participle. The chapter focuses on present/future, but this is a common extension.
  1. 1✗ Using 'cannot' instead of 'can't' for logical impossibility in informal contexts.
✓ That can't be true! (Correct: Common and natural)
✗ That cannot be true! (Less natural in everyday, conversational English for this specific meaning, though grammatically correct)
*Explanation:* While 'cannot' is grammatically fine, 'can't' is much more common and natural when expressing logical impossibility in conversational English.

Real Conversations

A

A

The lights are off in John's office. He usually works late.
B

B

He must have left already. It's almost 7 PM.
A

A

Do you think Sarah will come to the party?
B

B

She said she was busy, so she might not make it. But she may well surprise us if her meeting finishes early.
A

A

I can hear music from next door.
B

B

Oh, that can't be my neighbour. He's on holiday in Spain this week!

Quick FAQ

Q

Can I use 'may' and 'might' interchangeably for possibility?

Yes, in most cases for present and future possibility, may and might are interchangeable. Some people feel 'might' expresses a slightly weaker possibility, but the difference is very subtle and often not significant in everyday conversation.

Q

How is 'must' for possibility different from 'must' for obligation?

Must for possibility (epistemic) means

I am almost certain based on evidence
(e.g.,
He must be rich; he drives a fancy car.
). Must for obligation means
It is necessary or required
(e.g.,
You must finish your homework.
). The context makes the meaning clear.

Q

Is 'may well' much stronger than 'may'?

Yes, may well expresses a higher degree of probability than just may. It suggests that something is quite likely because there's a logical reason or expectation for it to happen. It's like saying "it's very likely or it's probable."

Q

When should I use 'can't' instead of 'won't be able to' for impossibility?

Use can't when you're making a logical deduction that something is impossible based on facts or evidence ("That can't be true, I saw it myself!"). Use 'won't be able to' for future inability or lack of opportunity ("I won't be able to come tomorrow, I have an appointment.").

Cultural Context

Native English speakers use these modal verbs constantly to soften statements, express uncertainty, and convey different levels of conviction. In casual conversation, you'll hear might and can't a lot, as they add a natural flow. Must for deduction is also very common.
While may well and might well are perfectly natural, they tend to be slightly more formal or used when explaining a reasoned prediction. There aren't significant regional differences in the core usage of these modals, but the frequency of their use may vary slightly between individuals.

Wichtige Beispiele (8)

1

I `may go` to the gym after work, if I'm not too tired.

Ich gehe vielleicht nach der Arbeit ins Fitnessstudio, wenn ich nicht zu müde bin.

Englische Möglichkeit: May und Might
2

They `might be` stuck in traffic, which is why they're late.

Sie stecken vielleicht im Stau, deshalb sind sie zu spät.

Englische Möglichkeit: May und Might
3

Look at all the snow! It `must be` freezing outside.

Sieh mal den ganzen Schnee! Es muss draußen eiskalt sein.

Logisches Vermuten mit 'Must' (epistemisch)
4

He's wearing a doctor's coat. He `must be` a doctor.

Er trägt einen Arztkittel. Er muss Arzt sein.

Logisches Vermuten mit 'Must' (epistemisch)
5

She **may well pass** the exam; she studied all week.

Es ist sehr wahrscheinlich, dass sie die Prüfung besteht; sie hat die ganze Woche gelernt.

Wahrscheinlichkeitsverstärker: May Well & Might Well
6

The package **might well arrive** tomorrow, as it shipped yesterday.

Das Paket kommt sehr wahrscheinlich morgen an, da es gestern verschickt wurde.

Wahrscheinlichkeitsverstärker: May Well & Might Well
7

That pizza place `can't be closed` already, it's only 8 PM!

Das Pizzarestaurant kann unmöglich schon geschlossen sein, es ist erst 20 Uhr!

Logische Unmöglichkeit (Das kann nicht sein!)
8

My internet `couldn't have gone out`. I just paid the bill yesterday.

Mein Internet kann nicht ausgefallen sein. Ich habe die Rechnung erst gestern bezahlt.

Logische Unmöglichkeit (Das kann nicht sein!)

Tipps & Tricks (4)

💡

Für höfliche Vorschläge

„Might“ ist super, um Ratschläge sanfter zu machen. Statt „Mach das“, sag lieber
You might want to consider this
, dann klingst du weniger aufdringlich und kollaborativer.
frontend.learn_grammar.from_rule: Englische Möglichkeit: May und Might
💡

Such nach den Beweisen!

Bevor du must für eine logische Vermutung benutzt, check immer, ob du handfeste Beweise hast. Je stärker der Beweis, desto sicherer bist du mit must.
The ground is wet, it must have rained.
frontend.learn_grammar.from_rule: Logisches Vermuten mit 'Must' (epistemisch)
💡

Gib deinen Vorhersagen mehr Gewicht

„May well“ und „might well“ verleihen deinen Prognosen eine zusätzliche Ebene der Zuversicht. Nutze sie, wenn du gute Gründe hast, etwas für wahrscheinlich zu halten, damit deine Sprache informierter und nuancierter klingt.
The company may well succeed.
frontend.learn_grammar.from_rule: Wahrscheinlichkeitsverstärker: May Well & Might Well
💡

Denk ans Gegenteil!

Stell dir vor, du würdest must be für eine starke positive Schlussfolgerung nutzen (z.B.
He must be rich
). Dann ist can't be genau das logische Gegenteil (z.B. "He can't be poor"). Das hilft dir, den logischen Zusammenhang besser zu verstehen.
frontend.learn_grammar.from_rule: Logische Unmöglichkeit (Das kann nicht sein!)

Wichtige Vokabeln (6)

Evidence facts or signs that show something is true Likelihood the chance that something will happen Certain completely sure about something Possible able to be done or happen Impossible not able to occur or exist Predict to say what will happen in the future

Real-World Preview

coffee

Solving an Office Mystery

Review Summary

  • Subject + may/might + base verb
  • Subject + must + base verb
  • Subject + can't + base verb

Häufige Fehler

In English, we do not use 'must not' for logical deductions. We use 'can't' to say something is logically impossible.

Wrong: It must be not true.
Richtig: It can't be true.

Modal verbs like 'might' never take an 's' in the third person singular.

Wrong: He mights come to the party.
Richtig: He might come to the party.

Adverbs of probability like 'probably' usually go after the first auxiliary verb or before the main verb.

Wrong: Probably I will see you later.
Richtig: I will probably see you later.

Next Steps

You've unlocked a new level of English! Being able to speculate and deduce makes your conversations much more interesting. Keep practicing those 'must be' moments!

Look out the window and make 5 'must be' and 5 'might be' observations about people you see.

Continue to: Collocations and Word Partnerships

Schnelle Übung (10)

Finde und korrigiere den Fehler

Find and fix the mistake:

If you don't save, you might as well run out of money.

✓ Correct! ✗ Not quite. Correct answer: If you don't save, you might well run out of money.
„Might well“ zeigt hier eine hohe Wahrscheinlichkeit an, dass dir das Geld ausgeht, wenn du nicht sparst, und nicht einen Vorschlag („might as well“).

frontend.learn_grammar.from_rule: Wahrscheinlichkeitsverstärker: May Well & Might Well

Fix the error.

Find and fix the mistake:

He is bound that he wins.

✓ Correct! ✗ Not quite. Correct answer: He is bound to win.
Bound to + infinitive.

frontend.learn_grammar.from_rule: Probability: Likely, Unlikely, Bound To, Definitely, Probably

Choose the correct sentence.

Which is correct?

✓ Correct! ✗ Not quite. Correct answer: I will probably go.
Probably before verb.

frontend.learn_grammar.from_rule: Probability: Likely, Unlikely, Bound To, Definitely, Probably

Finde und korrigiere den Fehler in der negativen logischen Vermutung.

Find and fix the mistake:

He must not be hungry; he just ate a huge burger.

✓ Correct! ✗ Not quite. Correct answer: He can't be hungry; he just ate a huge burger.
Für negative logische Vermutungen verwenden wir 'can't' oder 'couldn't', nicht 'must not'. 'Must not' impliziert ein Verbot.

frontend.learn_grammar.from_rule: Logisches Vermuten mit 'Must' (epistemisch)

Finde und korrigiere den Fehler im Satz.

Find and fix the mistake:

They mustn't be home. Their car isn't in the driveway.

✓ Correct! ✗ Not quite. Correct answer: They can't be home. Their car isn't in the driveway.
Mustn't be ist hier falsch. Der Sprecher zieht eine logische Schlussfolgerung basierend auf Beweisen (das Auto ist nicht da), daher ist can't be die passende Wahl, um logische Unmöglichkeit auszudrücken.

frontend.learn_grammar.from_rule: Logische Unmöglichkeit (Das kann nicht sein!)

Wähle die richtige Form, um logische Unmöglichkeit auszudrücken.

He's only 16, so he ___ a licensed driver yet.

✓ Correct! ✗ Not quite. Correct answer: can't be
Da er erst 16 ist, ist es logisch unmöglich, dass er schon einen Führerschein besitzt (in den meisten Orten). Can't be drückt diese Unmöglichkeit aus.

frontend.learn_grammar.from_rule: Logische Unmöglichkeit (Das kann nicht sein!)

Fill in the blank.

It is ___ to rain.

✓ Correct! ✗ Not quite. Correct answer: likely
Likely takes 'to'.

frontend.learn_grammar.from_rule: Probability: Likely, Unlikely, Bound To, Definitely, Probably

Wähle die richtige Form, um die logische Vermutung zu vervollständigen.

The lights are off and the door is locked. She ___ asleep.

✓ Correct! ✗ Not quite. Correct answer: must be
Für eine logische Vermutung in der Gegenwart verwende 'must' gefolgt von der Grundform des Verbs 'to be'.

frontend.learn_grammar.from_rule: Logisches Vermuten mit 'Must' (epistemisch)

Welcher Satz ist korrekt?

Choose the correct sentence:

✓ Correct! ✗ Not quite. Correct answer: He may well succeed.
Die korrekte Wortstellung für diese Phrase ist „may/might well + Grundform des Verbs“. Der Intensivierer 'well' steht direkt nach dem Modalverb.

frontend.learn_grammar.from_rule: Wahrscheinlichkeitsverstärker: May Well & Might Well

Wähle die korrekte Form

She's always late, so she ___ miss the bus.

✓ Correct! ✗ Not quite. Correct answer: may well
„May well“ drückt eine starke Wahrscheinlichkeit aus, basierend auf ihrer ständigen Verspätung. „May as well“ ist für Vorschläge, und „well may“ ist eine falsche Wortstellung.

frontend.learn_grammar.from_rule: Wahrscheinlichkeitsverstärker: May Well & Might Well

Score: /10

Häufige Fragen (6)

Die Hauptidee ist, auszudrücken, dass etwas möglich oder wahrscheinlich ist, aber nicht absolut sicher. Sie erlauben dir, zu spekulieren oder zu raten, ohne eine endgültige Aussage zu machen, wie zum Beispiel
It may rain later
oder
She might be busy
.
In den meisten modernen Kontexten, wenn es um Möglichkeiten geht, ja, sind sie weitgehend austauschbar. Während „might“ manchmal eine etwas geringere Wahrscheinlichkeit andeuten kann, ist der Unterschied im alltäglichen Sprachgebrauch oft sehr subtil und nicht konsistent zu beobachten.
Es geht darum, eine starke, sichere Schlussfolgerung zu ziehen, basierend auf den Beweisen, die du hast. Du sagst: 'Angesichts von X, muss Y wahr sein', weil es die einzige logische Schlussfolgerung ist.
Given X, Y must be true
.
Sehr sicher! Denk an 95-99% Wahrscheinlichkeit. Du benutzt 'must', wenn die Beweise so stark sind, dass die Schlussfolgerung fast unbestreitbar erscheint, wie zum Beispiel:
The lights are off, so he must be asleep.
„May well“ bedeutet, dass etwas sehr wahrscheinlich oder hochgradig wahrscheinlich ist, sicherer als nur „may“. Es impliziert einen logischen Grund für die erhöhte Wahrscheinlichkeit. Zum Beispiel:
It may well rain.
Sie sind für hohe Wahrscheinlichkeit weitgehend austauschbar. „Might well“ kann manchmal etwas zögerlicher sein oder für hypothetische Situationen verwendet werden, aber die Kernbedeutung hoher Wahrscheinlichkeit bleibt. Zum Beispiel:
She might well call later.
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