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.