B1 · 中级 章节 5

Expressing Cause, Path, and Rate with 'Por'

6 总规则
62 例句
5 分钟
本章规则 快速练习

Chapter in 30 Seconds

Master 'Por' to explain the 'why', 'how', and 'where' of your Portuguese journey.

  • Express the cause or reason behind any action or emotion.
  • Describe movement through spaces and the methods used to communicate.
  • Calculate rates, prices, and time durations accurately.
Connect your thoughts with the power of 'Por'.

你将学到什么

Hey, ready to level up your Portuguese? This chapter is all about 'Por' – that little word with HUGE power! You'll stop just getting by and start explaining things like a pro. Ever wondered how to say *why* something happened, or that you walked *through* a beautiful park? What about how much something costs *per* kilo, or that you studied *for* hours? 'Por' is your answer to all of these! We'll dive into its six main roles: explaining the *cause* or *reason* behind actions, describing *movement through a space* (like

walking along the river
), identifying the *means* or *method* of an action (sent by mail), and even talking about *rates* and *durations* of time (working per day). By understanding how 'por' connects these ideas – cause, path, method, rate, time – you'll unlock a whole new layer of expression. You'll master nuanced differences between 'por' and 'para', helping you avoid common mistakes intermediate learners make. After this, you'll effortlessly chat about *why* you love Portuguese, *how* you learned it, and *for how long* you've been practicing, making your conversations much more natural and engaging. Get ready to sound truly B1!

Learning Objectives

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

  1. 1
    By the end you will be able to explain the reason for an action using 'por causa de' or 'por' + noun.
  2. 2
    By the end you will be able to navigate a city by describing paths 'through' or 'along' specific landmarks.
  3. 3
    By the end you will be able to discuss prices per unit and frequency of habits per time period.

章节指南

Overview

Hey there, language learners! Ready to unlock a super versatile and incredibly common word in Portuguese grammar? This chapter is all about 'Por' – a tiny preposition with immense power that's absolutely crucial for reaching a B1 Portuguese level and beyond.
Mastering 'Por' will significantly boost your ability to express complex ideas, making your conversations much more natural and precise. You'll stop just translating word-for-word and start thinking like a native speaker. We'll explore how 'Por' helps you explain *why* something happened, describe *movement through a space*, identify the *means* or *method* of an action, and even talk about *rates* and *durations* of time.
By the end of this guide, you’ll effortlessly differentiate 'Por' from its sometimes-confusing cousin, 'Para', avoiding common intermediate mistakes and truly sounding like a pro. Get ready to express cause, path, and rate with confidence!

How This Grammar Works

The preposition 'Por' is a workhorse in Portuguese, connecting ideas in numerous ways. Let's break down its key functions, which are essential for any B1 Portuguese speaker.
First, 'Por' is fundamental for Expressing Cause & Reason. It tells us *why* something happens or *because of what*.
* Ele fez isso por amor. (He did that out of love.)
* A reunião foi adiada por causa da chuva. (The meeting was postponed because of the rain.)
Next, it's used for Expressing Cause, Exchange & Path. While cause is covered above, 'Por' also indicates exchange (like trading one thing for another) and movement along or through a path.
* Troquei meu carro por uma moto. (I exchanged my car for a motorcycle.)
* Caminhamos pela floresta. (We walked through the forest.) – Note pela is por + a.
This leads us to Portuguese Prepositions: Through and Along (Por). It describes movement *through* or *along* a place.
* Passamos por Lisboa. (We passed through Lisbon.)
* Andei pelo parque. (I walked through/along the park.) – Again, pelo is por + o.
'Por' is also vital for Means, Methods, and Agents. It specifies *how* an action is performed or *by whom* (in passive sentences).
* Enviei a carta por correio. (I sent the letter by mail.)
* O livro foi escrito por um autor famoso. (The book was written by a famous author.)
When talking about quantities or frequencies, we use 'Por' for Saying 'Per' or 'By': Rates with Por.
* Custa dez euros por quilo. (It costs ten euros per kilo.)
* Trabalho oito horas por dia. (I work eight hours per day.)
Finally, Por for Time (Duration & Approximation) indicates a duration of time or an approximate period.
* Estudei por três horas. (I studied for three hours.)
* Ele virá por volta das cinco. (He will come around five o'clock.)
Mastering these uses of 'Por' will significantly enhance your understanding of Portuguese grammar and your ability to communicate effectively.

Common Mistakes

  1. 1✗ Wrong: Fiz o trabalho para meu amigo. (I did the work for my friend.)
✓ Correct: Fiz o trabalho por meu amigo. (I did the work for my friend – *meaning on behalf of/instead of him*)
*Explanation:* While para often means for (purpose, destination), por is used when you do something *on behalf of* someone, or *in exchange for* them. If you did the work *for* your friend *so they could have it*, you might use para. But if you did it *because your friend couldn't*, por is correct.
  1. 1✗ Wrong: Viajamos para o trem. (We traveled to the train.)
✓ Correct: Viajamos de trem. (We traveled by train.) OR Viajamos por trem. (Less common, but still means by train).
*Explanation:* When referring to the means of transportation, de is most common. However, por can also be used for means/method, especially in more formal contexts or when emphasizing the *channel* through which something occurs. Para indicates destination, not the means of travel itself.
  1. 1✗ Wrong: Estudei para cinco horas. (I studied for five hours.)
✓ Correct: Estudei por cinco horas. (I studied for five hours.)
*Explanation:* To express a duration of time, por is the correct preposition. Para implies a purpose or destination, not how long an action lasted.

Real Conversations

A

A

Por que você está tão feliz hoje? (Why are you so happy today?)
B

B

Estou feliz por ter passado no exame! (I'm happy because I passed the exam!)
A

A

Você prefere viajar de carro ou por trem? (Do you prefer to travel by car or by train?)
B

B

Prefiro ir por avião, é mais rápido. (I prefer to go by plane, it's faster.)
A

A

A encomenda chegou por correio ou por uma transportadora? (Did the package arrive by mail or by a shipping company?)
B

B

Chegou por uma transportadora, foi entregue por um motorista. (It arrived by a shipping company, it was delivered by a driver.)

Quick FAQ

Q

What's the main difference between por and para when expressing purpose?

Para typically expresses purpose or destination (

for the sake of,
to), while por implies cause, reason, or exchange (because of, on behalf of, in exchange for).

Q

Can por always be replaced by pelo/pela?

Pelo (por + o) and pela (por + a) are contractions of por with definite articles. They are used when por is followed by a masculine or feminine singular noun, respectively. So, no, por isn't *always* replaced; it depends on whether an article follows.

Q

How do native speakers use por to talk about approximate time?

They often use phrases like por volta de (around/approximately) or simply por followed by a general time period, like por estes dias (around these days).

Cultural Context

In everyday Portuguese, 'Por' is incredibly common and often used fluidly. Native speakers might sometimes use 'por' in ways that seem subtle to learners, especially in idiomatic expressions. For instance,
obrigado por...
(thank you *for*...) is a fixed expression using por to indicate the reason for gratitude.
While regional accents and common phrases vary, the core grammatical functions of 'por' remain consistent across Brazil and Portugal, making it universally understood and essential for authentic communication.

关键例句 (6)

1

Eu paguei uma fortuna pelo novo iPhone.

I paid a fortune for the new iPhone.

介词 Por：表达原因、交换和路径
2

Vamos passar pelo parque para chegar mais cedo.

Let's go through the park to arrive earlier.

介词 Por：表达原因、交换和路径
3

Eu caminhei pelo parque hoje de manhã.

I walked through the park this morning.

葡萄牙语介词：穿过与沿着 (Por)
4

Ela gosta de correr pela praia ao pôr do sol.

She likes to run along the beach at sunset.

葡萄牙语介词：穿过与沿着 (Por)
5

Eu vou ao ginásio três vezes **por** semana.

我每周去三次健身房。

表达“每”或“按”：使用 Por 的比率 (por dia, pelo quilo)
6

O limite de velocidade é 120 km **por** hora.

限速是每小时120公里。

表达“每”或“按”：使用 Por 的比率 (por dia, pelo quilo)

技巧与窍门 (4)

⚠️

"Pum" 法则

千万别把 'por' 和 'um' 连读。要分开说：'por um'。连读听起来像 pum（放屁的声音），这可是聊天终结者！比如：
Ele esperou por um momento.
frontend.learn_grammar.from_rule: 葡萄牙语介词 'Por'：表达原因和理由
💡

Check the article

Whenever you see 'por' followed by 'o', 'a', 'os', or 'as', always contract it!
frontend.learn_grammar.from_rule: 介词 Por：表达原因、交换和路径
💡

Contractions are mandatory

Never write 'por o' or 'por a'. Always use 'pelo' or 'pela'.
frontend.learn_grammar.from_rule: 葡萄牙语介词：穿过与沿着 (Por)
💡

WhatsApp 规则

谈论 App 或网站时，几乎总是用 pelo，因为 aplicativo 和 site 都是阳性。例如：Mandei pelo WhatsApp.
frontend.learn_grammar.from_rule: 葡萄牙语介词 'Por'：手段、方法与施事者

核心词汇 (7)

motivo reason troca exchange caminho path/way correio mail quilo kilogram durante during (often synonymous with por in time) através through

Real-World Preview

shopping-cart

At the Local Market

clock

Explaining a Delay

Review Summary

  • Verbo + por + Substantivo
  • Verbo de Movimento + pelo/pela + Local
  • Número + por + Unidade

常见错误

Use 'para' for purpose (to do something) and 'por' for cause. Since seeing birds is the goal/purpose, 'para' is required.

Wrong: Vou para o parque por ver os pássaros.
正确: Vou ao parque para ver os pássaros.

In Portuguese, 'por' must contract with definite articles. 'Por' + 'a' always becomes 'pela'.

Wrong: Eu ando por a rua.
正确: Eu ando pela rua.

In passive voice, the agent (the person doing the action) is introduced by 'por', not 'para'.

Wrong: O livro foi escrito para Machado de Assis.
正确: O livro foi escrito por Machado de Assis.

Next Steps

You've just unlocked one of the most versatile tools in the Portuguese language. Your ability to explain reasons and paths will make your conversations much more fluid. Keep practicing those contractions!

Narrate your walk to work/school using 'pelo/pela'.

Look at a grocery receipt and state prices 'por quilo'.

Continue to: Nuanced Comparisons and Passive Actions

快速练习 (10)

Correct the sentence.

Find and fix the mistake:

Fiz isso por o meu pai.

✓ Correct! ✗ Not quite. Correct answer: Fiz isso pelo meu pai.
Por + o = pelo.

frontend.learn_grammar.from_rule: 葡萄牙语介词：穿过与沿着 (Por)

Find the error.

Find and fix the mistake:

Fiz isso por que você pediu.

✓ Correct! ✗ Not quite. Correct answer: porque
Conjunction is 'porque'.

frontend.learn_grammar.from_rule: 介词 Por：表达原因、交换和路径

在空格处填入正确的缩合形式（pelo, pela, pelos, pelas）。

Ela está muito feliz ___ novo emprego.

✓ Correct! ✗ Not quite. Correct answer: pelo
'Emprego' 是阳性单数名词，所以我们用 'por' + 'o' = 'pelo'。

frontend.learn_grammar.from_rule: 葡萄牙语介词 'Por'：表达原因和理由

哪句话正确表达了沟通方式？

选择正确的选项：

✓ Correct! ✗ Not quite. Correct answer: Eu vi a notícia pela internet.
我们用 'pela' (por + a) 来修饰 'internet'，表示媒介或手段。

frontend.learn_grammar.from_rule: 葡萄牙语介词 'Por'：手段、方法与施事者

找出并修正这句话中关于原因的错误。

Não saímos por a chuva forte.

✓ Correct! ✗ Not quite. Correct answer: Não saímos pela chuva forte.
'Chuva' 是阴性单数。'Por' + 'a' 必须缩合为 'pela'。

frontend.learn_grammar.from_rule: 葡萄牙语介词 'Por'：表达原因和理由

完成这个关于频率的短语。

Eu bebo café duas vezes ___ dia. (我每天喝两次咖啡)

✓ Correct! ✗ Not quite. Correct answer: por
对于频率（每个时间段多少次），我们总是使用 'por'。

frontend.learn_grammar.from_rule: 表达“每”或“按”：使用 Por 的比率 (por dia, pelo quilo)

Fill in the blank with the correct contraction.

Caminhei ___ (por + a) rua.

✓ Correct! ✗ Not quite. Correct answer: pela
Por + a = pela.

frontend.learn_grammar.from_rule: 介词 Por：表达原因、交换和路径

Fill in the blank.

O projeto foi aprovado ___ diretoria.

✓ Correct! ✗ Not quite. Correct answer: pela
Diretoria is feminine.

frontend.learn_grammar.from_rule: 葡萄牙语介词：穿过与沿着 (Por)

Choose the correct form.

___ você não veio?

✓ Correct! ✗ Not quite. Correct answer: Por que
Question form requires two words.

frontend.learn_grammar.from_rule: 葡萄牙语介词：穿过与沿着 (Por)

Choose the correct preposition.

Vou ___ (por/para) Lisboa amanhã.

✓ Correct! ✗ Not quite. Correct answer: para
Destination requires para.

frontend.learn_grammar.from_rule: 介词 Por：表达原因、交换和路径

Score: /10

常见问题 (6)

在葡语中，为了发音顺滑，介词必须与冠词缩合。'Por' + 'o' 演变成了 pelo。这在口语和书面语中都是强制性的。
当你想要非常明确地强调原因时使用它。就像说“专门因为...”而不是简单的“因为”。例如：
Por causa de você.
Usually, yes. You can also use 'por causa de', but 'por' is more concise.
Yes, for duration (e.g., 'por duas horas').
Use 'pelo' when 'por' is followed by the masculine article 'o'. It is a mandatory contraction.
It is common, but in informal Brazilian Portuguese, it is often omitted.
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The Rules of Pronoun Placement
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Nuanced Comparisons and Passive Actions
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