问题
选择题
I got up early that morning, but I _____ so because I had no work to do.
A．mustn’t have done
B．didn’t need to do
C．needn’t have done
D．can’t have done
答案
答案：C
needn’t have done表示“过去不必做而做了某事”，若表示“不必做某事（且实际上未做）”则用“didn’t / don’t / doesn’t need to.”