as the need arises

• 需要时； 必要时

as the need arises的用法和样例：

例句

1. Take money from the bank as the need arises.
   需要时，把钱从银行里取出来。
2. I knew you would help me in my hour of need.
   我知道你会在我需要时帮助我的。
3. We can put up ten people for the night at a pinch.
   必要时我们可以留宿十个人。
4. She can needle herself if need be.
   必要时她会给她自己打针的。