promise to do what is needful
答应做必须做的事.
What must be done, must be done.
必须做的事情就必须做。
We must do all that is to be done.
我们必须做该做的事。
I'll do what I must.
我必须做我该做的事。
Is there anything that I have to do?
有什么必须做的事吗？
Leisure does what it likes; labor does what it must.
闲暇是做你喜欢做的事，而劳动是你必须做的事。
make a virtue of necessity
把必须做的事装成出于好心做的
You must do what ought to be done after due reflection .
在适当考虑之后，你必须做要做的事。
You must give your full attention to what you are doing.
你必须全神贯注地做你所做的事.
The unfinished business of yesterday must take precedence of new business.
昨天未了的事必须比今天的事先做。
Harry has to fight against bad wizards and do the right thing.
哈利必须和坏巫师作斗争，必须做正确的事情。
be necessary (for one) to do something (go somewhere)
（某人）必须做某事（去某处）
You must do it beyond all things.
你首先必须做这件事。
We'll have to go about it more carefully.
我们必须细心去做此事。
I have to do what I'm going to do and just let it happen."
我必须做我准备做的事情，让我们拭目以待吧。”
What I do must meet the interests of our company.
我做的事必须符合公司的利益。
In order to accomplish this, it is essential to have a stable political environment.
要做这样的事，必须有安定的政治环境。
The first thing you must do is to turn off the light.
你必须做的第一件事是关掉灯。