(1)may/might (just) as well“不妨，最好”，与had better相近。如：Since the flight was cancelled, you might as well go by train.
You cannot be too careful when you drive a car.
The final chapter covers organizational change and development. This subject cannot be overemphasized.
(3)usedn’t或didn’t use to为used to (do)的否定式。
(4)should 除了“应该”一层意思外，大纲还规定要掌握其“竟然”的意思。如：I didn’t expect that he should have behaved like that.