required

• 指因规则、法律或情况而必须的、必不可少的。也表示规定或要求的。

Describes something that is necessary or needed according to rules, laws, or circumstances.

1. Necessary or mandatoryB1formal

   Something that must be done or possessed because of a rule, law, or need.

   必需的

   • A valid passport is required for international travel.
   • The required documents must be submitted by Friday.
   • Safety training is required for all new employees.

   同义词compulsoryessentialimperativeindispensablemandatorynecessaryneededobligatoryrequisitevital

   反义词nonessentialoptionalunnecessaryvoluntary

2. Essential for a purposeB1formal

   Needed in order to achieve a particular result or function.

   必需的

   • The required amount of water for the recipe is two cups.
   • Patience is required when learning a new language.
   • The required skills for this job include programming and teamwork.

   同义词crucialessentialimperativeindispensablenecessaryneededrequisitevital

   反义词dispensablenonessentialoptionalunnecessaryvoluntary

• 动词，表示需要某事物，或要求某事物是必须的、必不可少的。

A verb used to indicate the need for something or to demand something as necessary or essential.

1. Need or demandB1formal

   To need something or make something necessary.

   需要

   • This recipe requires three eggs.
   • The job requires a lot of patience.
   • All passengers are required to show their tickets.

   同义词call fordemandentailinvolvenecessitateneed

2. Order or compelB1formal

   To officially demand that someone does something, often by rule or law.

   要求

   • The law requires drivers to wear seat belts.
   • Students are required to attend all classes.
   • The contract requires both parties to sign.

   同义词commandcompeldemanddirectenjoinmandateobligeorder

   反义词allowbanforbidpermitprohibit