1) should和ought to表示责任、建议或劝告，翻译为“应该”，后者语气强一些。
【例如】
You should listen to the doctor's advice if you want to recover soon.
Such things ought not to be allowed.
2) should接动词的完成式，是一种谴责，表示过去应该做而没有做或过去做了而不应该做。
【例如】
I missed the class. I should have come earlier.
I shouldn't have made such a foolish mistake.