act

/ækt/ (bre, ipa) · [ˈækt] /ækt/ (ame, ipa) · [ˈækt] /ˈakt/ (ame, mw)

act — verb

  • actpresent simple I / you / we / they
  • actshe / she / it
  • actedpast simple
  • acting-ing form

1. to show a certain manner through what you say or do

1.動詞不及物A2
釋義

to show a certain manner through what you say or do

例句

Greta acted calmly while the fire alarm rang in the library.

act + adverb

At the clinic, Christopher acted politely even after a long wait.

同義詞

文法句型

act + adverb

act like + noun

用法筆記

Often followed by an adverb or by like + noun to show the manner of behaviour.

常見錯誤

He did very calm in class.
He acted very calmly in class.
💡use 'act' when you describe behaviour, not 'do'.

2. to step in and do what is needed for a problem or goal

2.動詞不及物B2
釋義

to step in and do what is needed for a problem or goal

例句

Joon acted quickly and moved the children away from the broken glass.

act quickly

After the leak spread, Tanvi acted to close the kitchen valve.

act + to infinitive

同義詞
  • respond

    usually follows a clear event or warning

  • intervene

    suggests stepping in to change a situation

文法句型

act + quickly

act + to infinitive

act on behalf of + person

用法筆記

Used when someone stops waiting and does something practical. Distinguish from sense 1, which describes manner rather than a step taken.

常見錯誤

The town acted a new plan.
The town acted to start a new plan.
💡this sense is usually intransitive, often followed by 'to'.

3. to start changing something or producing a result

3.動詞不及物B2
釋義

to start changing something or producing a result

例句

The pain medicine acted within minutes and eased Marta's back.

act within + time

Warm water acts faster when dry glue covers a thin layer.

同義詞
  • work

    more general and common in everyday speech

  • affect

    focuses on the result rather than the process

文法句型

act on + object

act quickly/slowly

用法筆記

Often used for medicine, heat, light, or chemicals. The pattern 'act on' names the thing that is changed.

4. to appear as a character before an audience or camera

4.動詞及物 / 不及物B1
釋義

to appear as a character before an audience or camera

例句

Shirin acted the mother in the school play on Friday.

act + role

Linh wants to act in films after finishing drama college.

act in + film

同義詞
  • perform

    broader and can apply outside acting roles

  • play

    especially common before the role name

文法句型

act in + play/film

act the part of + role

用法筆記

Use 'act in' for appearing in a production and a direct object for the role itself.

5. to behave badly or in a foolish way

5.動詞不及物B2
釋義

to behave badly or in a foolish way

例句

Andrew kept acting the fool and made the younger children cry.

act the fool

At dinner, Harper acted badly and threw rice onto the floor.

同義詞

文法句型

act the fool

act + adjective

act like + noun

用法筆記

Often used when someone behaves in an annoying, childish, or rude way. Distinguish from sense 6, which is about pretending rather than simple bad behaviour.

6. to pretend to have a feeling, quality, or identity

6.動詞不及物B2
釋義

to pretend to have a feeling, quality, or identity

例句

Yara acted brave, but her hands shook under the desk.

act + adjective

When the bill arrived, Eitan acted surprised and checked his empty wallet.

同義詞
  • pretend

    the closest everyday synonym

  • feign

    more formal and often used for feelings

文法句型

act + adjective

act as if + clause

act like + noun

用法筆記

Usually suggests that the behaviour is not genuine. Distinguish from sense 7, where the person or thing really performs the role named after as.

7. to do the job of a person or thing, or be used for a purpose

7.動詞不及物B2
釋義

to do the job of a person or thing, or be used for a purpose

例句

Wren acted as team captain while the coach stayed in hospital.

act as + role

The hall acted as a shelter after the storm damaged homes.

act as + purpose

同義詞
  • serve

    broadly means do a role or purpose

  • function

    stresses the use or purpose of a thing

文法句型

act as + role

act as + purpose

用法筆記

This sense is about a real role or function. It can describe a person, place, tool, or system.

act — noun