shouldn't have done/needn't have done

上面两个句子的意思是有区别的。shouldn't have done 表示“本不应该做某事，而实际上却做了”，有时含有批评、责备或婉惜的意思。needn't have done 表示“本不必做某事，而实际上却做了”，不一定含有批评、责备的含义。

1. You should not have gone up to college so soon. (But you did) 你本不应该这么早就上大学的。

2. She shouldn't have stood in a queue. 她本不应该排长队的。

3. You needn't have walked up; you could have taken the lift. 你本不必走上去的；你可以乘电梯嘛。

4. You neendn't have mentioned it, Mother. 妈妈,你本不必提这件事的。