B1 · 中級 チャプター 13

Rules, Advice, and Instructions

4 トータルルール
48 例文
6 分
このチャプターのルール クイック練習

Chapter in 30 Seconds

Master the art of giving helpful advice and clear instructions with confidence.

  • Suggest better choices using the modal verb should.
  • Express non-negotiable rules and necessities using must.
  • Link specific conditions to advice and direct commands.
Command the room and guide others with precision.

学べること

Feeling ready to give advice and strong instructions like a pro? This chapter will show you how to use if with commands and express what must be done, helping you guide others clearly and effectively in everyday conversations.

Learning Objectives

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

  1. 1
    By the end you will be able to offer polite recommendations for common problems using should.
  2. 2
    By the end you will be able to state firm legal or personal requirements using must.
  3. 3
    By the end you will be able to construct complex conditional sentences to give advice based on specific situations.

チャプターガイド

Overview

As you continue your journey in B1 English grammar, you’re building the skills to connect with people and express yourself clearly in a wide range of situations. This chapter is all about giving effective English rules, advice, and instructions. Imagine being able to help a friend, offer clear guidance, or explain important steps without sounding aggressive or unclear.
That's exactly what you'll learn here!
We'll dive into the subtle art of using words like should to offer helpful recommendations, like
You should try that new cafe.
You'll also master must for those times when something is truly essential, as in
You must submit your report by Friday.
We’ll also explore how to combine these with the first conditional – using if clauses to give advice and commands that are relevant to specific situations, such as
If you want to pass the exam, you should study every day
or
If you see a problem, tell your manager immediately.
By the end, you'll be confidently guiding others and understanding important directions like a native speaker.

How This Grammar Works

Learning to give and understand rules, advice, and instructions effectively makes your English sound much more natural and confident. Let's explore how these pieces fit together, moving from gentle suggestions to strong directives.
First, for friendly advice and recommendations, we use should. This is your go-to for suggesting the best course of action without being too strong or bossy. For example,
You should drink more water
or
They should call their parents more often.
It implies a good idea, but the choice is still up to the listener.
When something is absolutely essential, a strong obligation, or a logical necessity, we use must. This isn't a suggestion; it's a rule, a requirement, or something that is highly certain. Think of signs like
All visitors must check in at reception
or personal vows like
I must finish this project tonight.
If there’s no other option, or the consequences of not doing it are serious, must is the word.
Now, let's add a condition! The first conditional for advice (should) combines a possible future situation with advice. The structure is simple: If + present simple, should + base verb.
This allows you to give advice that is specific and relevant to a particular scenario. For instance,
If you feel tired, you should take a break
or
If it rains tomorrow, we should bring umbrellas.
This makes your advice more practical and targeted.
Finally, we have the first conditional for commands & advice (If + Imperative). Here, instead of using should, you give a direct command or instruction in the second part of the sentence. The structure is: If + present simple, imperative (base verb form).
For example,
If you arrive late, wait outside
or
If you have any questions, ask the teacher.
This is perfect for giving clear, actionable instructions based on a potential future event. These structures together give you a powerful toolkit for guiding conversations and ensuring clarity in your interactions.

Common Mistakes

It's easy to mix up these useful phrases. Here are some common pitfalls and how to avoid them:
  1. 1✗ Wrong: You must try the new coffee shop. (Sounds too strong, like an order)
✓ Correct: You should try the new coffee shop. (A friendly recommendation)
*Explanation:* Use should for suggestions, not must, which implies a necessity or obligation.
  1. 1✗ Wrong: If you want to lose weight, you must to exercise. (Incorrect grammar with to)
✓ Correct: If you want to lose weight, you must exercise. (Correct verb form)
*Explanation:* After modal verbs like must or should, always use the base form of the verb without to.
  1. 1✗ Wrong: If it rains, you should to take an umbrella. (Incorrect grammar with to)
✓ Correct: If it rains, you should take an umbrella. (Correct verb form)
*Explanation:* Like with must, should is followed directly by the base verb form.

Real Conversations

Here’s how these grammar points appear in everyday chats:

A

A

"I'm really struggling with my English homework. It's so difficult!"
B

B

"Oh, really? If you're having trouble, you should ask the teacher for help during office hours. She's very approachable."
A

A

"My flight leaves at 6 AM tomorrow. I'm worried I'll miss it."
B

B

"Wow, that's early! You must set several alarms, and you should pack your bag tonight so you don't forget anything important."
A

A

"I'm going hiking this weekend, but the weather forecast looks a bit unpredictable."
B

B

If the weather changes suddenly, make sure you have a map and a fully charged phone. And if it starts raining heavily, turn back immediately!

Quick FAQ

Q

When should I use should versus must for advice?

Use should for advice, recommendations, or what's generally a good idea. It's a suggestion. Use must when there's a strong obligation, a rule, a necessity, or a strong personal conviction. It implies no real choice.

Q

Can I use if with must?

While grammatically possible (e.g.,

If you must leave, please close the door
), it's less common for *giving advice*. It usually expresses a resignation or necessity already acknowledged. For conditional advice, stick to should or an imperative.

Q

Is you should always polite?

Generally, yes, you should is polite. However, if used too frequently or with a lecturing tone, it can sometimes sound a little preachy. To soften it further, you can say

I think you should...
or
Perhaps you should...

Q

What's the difference between

If you want to...
and
If you need to...
when giving advice?

If you want to...
implies a personal desire or goal (e.g.,
If you want to improve, you should practice daily
).
If you need to...
implies a requirement or necessity (e.g.,
If you need to contact me, call this number
). Both are useful in conditional advice.

Cultural Context

In English, the way we give advice and instructions often reflects politeness and directness. While must clearly states an obligation, it can sometimes sound very direct, almost like an order, especially in informal contexts. Native speakers often prefer should or softer phrases (like
You might want to...
or I suggest you...) even for important advice, to maintain a friendly tone.
Using the first conditional with an imperative ("If you're cold, put on a jacket") is common and generally accepted as clear and direct, but still contextual. Understanding these nuances helps you sound more natural and avoid accidental rudeness.

重要な例文 (8)

1

You `should really try` the new coffee shop downtown; their lattes are amazing.

街の新しいカフェ、本当に試してみるべきだよ。ラテが最高だからね。

アドバイスや推奨事項を提供する (Should)
2

I think we `should start` our project early to avoid any last-minute stress.

ギリギリで焦らないように、プロジェクトは早めに始めた方がいいと思うな。

アドバイスや推奨事項を提供する (Should)
3

You **must** hand in your assignment by Friday.

金曜日までに課題を提出しなければなりません。

Must: 強い義務と必要性
4

I **must** remember to call my parents tonight.

今夜、両親に電話することを忘れずにいなければなりません。

Must: 強い義務と必要性
5

`If you're hungry, you should grab a snack.`

お腹が空いたら、軽食を取るべきですよ。

助言のための第一条件文 (should)
6

`If it rains later, you should take an umbrella with you.`

もし後で雨が降るなら、傘を持って行くべきです。

助言のための第一条件文 (should)
7

`If you feel cold, close the window.`

Si tienes frío, cierra la ventana.

第一条件: 命令とアドバイス (If + 命令形)
8

`If you're hungry, grab a snack from the fridge.`

Si tienes hambre, coge un aperitivo de la nevera.

第一条件: 命令とアドバイス (If + 命令形)

ヒントとコツ (4)

💡

優しく伝えましょう

「should」は、きつい命令ではなく、優しい提案の言葉です。相手に同意を促す形で、アドバイスが受け入れられやすくなります。強い義務には「must」を使ってくださいね。例えば、「You should try this new recipe.」
frontend.learn_grammar.from_rule: アドバイスや推奨事項を提供する (Should)
💡

「強い義務」だと考えてみましょう

もし「絶対に〜する必要がある」とか「〜という規則だ」と言い換えられるなら、「must」がぴったりです。「should」よりも強い意味になります。「You must submit this form by Friday.」
frontend.learn_grammar.from_rule: Must: 強い義務と必要性
💡

「If」節では現在形を使う

たとえ未来の可能性について話している時でも、「if」の節では必ず「現在形」を使いましょう。未来の意味は、主節の「should」から伝わります。「もし明日晴れたら、公園に行くべきだよ」
If it is sunny tomorrow, you should go to the park.
frontend.learn_grammar.from_rule: 助言のための第一条件文 (should)
💡

命令形で「直接的」に伝えよう

命令形を使うときは、動詞の原型をそのまま使いましょう。「will」や「should」をメインの節に加えると、意味が「予測」や「提案」に変わってしまうので注意してくださいね。直接的な指示ではなくなってしまいます。「If you need help, ask me.」
frontend.learn_grammar.from_rule: 第一条件: 命令とアドバイス (If + 命令形)

重要な語彙 (6)

recommend to suggest something as a good choice mandatory required by law or rules passenger a person traveling in a vehicle instruction detailed information on how to do something prohibit to formally forbid something advice guidance or recommendations

Real-World Preview

plane

At the Airport Security

stethoscope

A Visit to the Doctor

Review Summary

  • Subject + should + Verb (base form)
  • Subject + must + Verb (base form)
  • If + Present Simple, Subject + should + Verb (base)
  • If + Present Simple, [Imperative Verb]

よくある間違い

Modal verbs like 'should' and 'must' are followed directly by the base verb. Never use 'to' after them.

Wrong: You should to study more.
正解: You should study more.

In conditional advice, the second clause still needs a subject (you, he, she) before the word 'should'.

Wrong: If you are hungry, should eat.
正解: If you are hungry, you should eat.

In the 'if' clause of a first conditional, we use the Present Simple, not 'will'.

Wrong: If you will see him, tell him the news.
正解: If you see him, tell him the news.

Next Steps

You've taken a huge step toward fluency! Being able to guide others is a key leadership skill in any language. Keep practicing these patterns and you'll be a master communicator in no time.

Write 5 rules for your favorite sport using 'must' and 'should'.

Look at a recipe and identify the conditional instructions.

Continue to: Talking About Facts and Constant Truths

クイック練習 (10)

文章の間違いを見つけて修正しましょう。

`If you are tired, you will go to bed.`

✓ Correct! ✗ Not quite. Correct answer: If you are tired, go to bed.
2つ目の節は命令形（直接的な命令）の「go to bed」であるべきで、「will」を使った予測ではありません。

frontend.learn_grammar.from_rule: 第一条件: 命令とアドバイス (If + 命令形)

文中の間違いを見つけて修正しましょう。

Find and fix the mistake:

They should to call before visiting.

✓ Correct! ✗ Not quite. Correct answer: They should call before visiting.
助動詞「should」の後には、動詞の原形が「to」なしで続きます。

frontend.learn_grammar.from_rule: アドバイスや推奨事項を提供する (Should)

文中の間違いを見つけて修正してください。

Find and fix the mistake:

If she will arrive late, she should call us.

✓ Correct! ✗ Not quite. Correct answer: If she arrives late, she should call us.
First Conditionalの「if」節では現在形を使います。したがって、「will arrive」は間違いで、「arrives」が正しいです。

frontend.learn_grammar.from_rule: 助言のための第一条件文 (should)

アドバイスを完成させるのに正しい形を選びましょう。

You ___ remember to save your work frequently.

✓ Correct! ✗ Not quite. Correct answer: should
ここでは「should」がアドバイスやおすすめをするために使われ、作業を頻繁に保存するのが良いアイデアであることを示しています。

frontend.learn_grammar.from_rule: アドバイスや推奨事項を提供する (Should)

アドバイスを完成させる正しい形を選んでください。

If you have a headache, you ___ take some medicine.

✓ Correct! ✗ Not quite. Correct answer: should
アドバイスをする際には「should」を使います。「will」は結果を予測し、「can」は能力を表します。

frontend.learn_grammar.from_rule: 助言のための第一条件文 (should)

文章を完成させる正しい命令形の動詞を選びましょう。

`If you see a good movie playing, ___ me about it!`

✓ Correct! ✗ Not quite. Correct answer: tell
「if」節の後は、直接的な命令のために動詞の原型を使います。

frontend.learn_grammar.from_rule: 第一条件: 命令とアドバイス (If + 命令形)

正しい文章になるように単語を並べ替えましょう。

これらの単語を並べ替えて文章を作りましょう:

✓ Correct! ✗ Not quite. Correct answer: If you get lost, call me.
正しい順序は「If + 主語 + 現在形, 命令形 + 目的語」です。

frontend.learn_grammar.from_rule: 第一条件: 命令とアドバイス (If + 命令形)

正しいアドバイスの文を選びましょう。

Choose the correct sentence:

✓ Correct! ✗ Not quite. Correct answer: She should study harder for the test.
「should」の後には動詞の原形（study）が続きます。「studies」ではありません。「must to」は間違いです。「must」の後には「to」はつけません。

frontend.learn_grammar.from_rule: アドバイスや推奨事項を提供する (Should)

文を完成させるために正しい形を選びましょう。

You ___ remember your passport for international travel.

✓ Correct! ✗ Not quite. Correct answer: must
「Must」は助動詞で、その後に「to」や「-s」なしで動詞の原形が続きます。

frontend.learn_grammar.from_rule: Must: 強い義務と必要性

文の間違いを見つけて直しましょう。

Find and fix the mistake:

We must to study for the final exam.

✓ Correct! ✗ Not quite. Correct answer: We must study for the final exam.
「must」のような助動詞の後は、動詞の原形が直接続きます。「to」は間違いです。

frontend.learn_grammar.from_rule: Must: 強い義務と必要性

Score: /10

よくある質問 (6)

「should」は、何かをすることが「良いアイデア」である、または「一般的に期待される」という意味が主です。アドバイス、おすすめ、優しい提案をする時に使われます。親切な「後押し」のようなものだと思ってください。「You should try it!」
もちろんできます！自分自身への提案や、自分にとって何が最善かを考える時に「should」を使えます。例えば、「I should probably get some sleep.」とか「I should start that project soon.」のようにね。
A: 「must」は主に、強い義務、必要性、または禁止を表現するために使われます。しっかりとした「required（必須）」や「not allowed（許可されない）」と考えてみましょう。「You must complete this task.」
A: いいえ、「must」は助動詞なので、規則動詞とは異なる振る舞いをします。主語や時制によって形が変わることはありません。「I must go.」「She must go.」
これは、未来の現実的で可能性のある状況についてアドバイスや推奨をするためのものです。「もしXが起こるなら、Yをすべきだ」と伝える時に使います。「If you are cold, you should wear a coat.」のように、特定の状況に対する行動を提案します。
「will」を使う通常のFirst Conditionalは、特定の起こりうる結果を予測します（例：「If it rains, we will stay home」）。一方で、「should」を使う場合は、提案やアドバイスを提供します（例：「If it rains, you should take an umbrella」）。
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