constrain

constrain — verb

1. to put a limit on how something can develop, be done, or change — for example, w

1.動詞及物B2
釋義

to put a limit on how something can develop, be done, or change — for example, when a shortage of money stops a school from hiring enough teachers, or when rules control what companies are allowed to do.

例句

The drought severely constrained the amount of food that local farmers could grow.

constrain + noun phrase (amount of food)

It was frustrating for the team to be constrained by such tight deadlines.

passive: be constrained by [deadline/limit]

同義詞
  • restrict

    More common in everyday English; used especially for rules and physical limits

  • limit

    The broadest and most common word; covers any boundary on size, amount, or ability

  • curb

    More formal; suggests actively holding something back, often something undesirable

反義詞
  • free

    To remove limits or restrictions

  • liberate

    To set free from constraints, often in a broader or more formal sense

文法句型

constrain + noun phrase

be constrained by + noun phrase

用法筆記

Frequently used in the passive voice. The subject is typically an external factor such as a budget, law, space, or rule — not a person who actively restricts someone. Common in formal, academic, and professional writing.

常見錯誤

❌The new dress code constrained employees to wear formal clothes.
✅The new dress code required employees to wear formal clothes.
💡'constrain' is about limiting options, not about stating a simple requirement.
❌She constrained the door with a heavy lock.
✅She secured the door with a heavy lock.
💡'constrain' is not used for physically locking or blocking something in everyday English.

2. to put pressure on someone so that they must act or choose in a certain manner b

2.動詞及物B2
釋義

to put pressure on someone so that they must act or choose in a certain manner because of a rule, promise, duty, or set of circumstances — for example, when a contract obliges a business to deliver goods by a certain date, or when a promise stops someone from sharing secret information.

例句

The contract constrained Pim to deliver the goods by the end of March.

constrain + pronoun + to-infinitive

Judges are constrained to apply the law exactly as it is written.

passive: be constrained to + infinitive

同義詞
  • force

    Stronger and more direct; can describe personal or physical pressure

  • compel

    Similar register to 'constrain'; often used in legal or formal contexts

  • oblige

    Less strong; suggests duty rather than strict limitation of choice

反義詞
  • free

    To release from an obligation or limitation

  • release

    To let someone go from a duty or promise

文法句型

be constrained to + infinitive

feel constrained to + infinitive

用法筆記

Most common in the passive voice followed by a to-infinitive ('be constrained to do something'). The agent of the constraint is usually an obligation, promise, contract, or circumstance — not typically another person. 'Feel constrained to' adds a sense of personal reluctance.

常見錯誤

❌Her parents constrained her to study every evening.
✅Her parents forced her to study every evening.
💡'constrain' is not typically used with a person as the active agent of pressure; use 'force' or 'make' instead.
❌I constrained him to come to the party.
✅I persuaded him to come to the party.
💡'constrain' implies a serious limitation of choice, not casual persuasion.