required

基本解释

The police required the traveler to unlock his suitcase.
警察要求这位旅客将手提箱打开。
Jane was the only one who fulfilled all the conditions; she was of the required age, height and colour.
简是惟一满足所有条件的人，她具备所要求的年龄、身高和肤色。
A remittance of a large sum is required.
要求一笔大数额的汇款。
《新英汉大辞典》

His education law,still in effect, required states to show yearly progress in student learning as measured by the states' own tests.
And so when we say something is exponential, we're talking about in terms of the number of bits required to represent it.
所以当我们说某些东西，是指数增长的我们指的,就是代表它的比特数。
麻省理工公开课 - 计算机科学及编程导论课程节选
I think that if a classroom devolves to the point where physical force is required to gain control,
我认为，如果一个课堂秩序十分混乱，以至于要用武力来维持秩序，
反对体罚 - SpeakingMax英语口语达人

So serious was her crime that it required 14 policemen in two vans to arrest her.
UNESCO: Of T-shirts and a vegan commemoration…

If you require something or if something is required, you need it or it is necessary.
If a law or rule requires you to do something, you have to do it.