Definition
the minimum acceptable action or behavior that one should do in a particular situation.
至少应该做的事
In this situation, the least you could do is apologize.
在这种情况下，你至少应该道歉。
Having made such a big mistake, the least she could do is take responsibility.
犯了这么大的错误，她至少应该承担责任。
They criticized you at the meeting, the least you could do is defend yourself.
他们在会议上批评了你，你至少应该为自己辩护。