You look tired. You’d better up late.A. stayB. not stayC. to not stayD. not to stay

问题补充：

You look tired. You’d better up late.

A. stay

B. not stay

C. to not stay

D. not to stay

答案：

A. stay

(答案→)B. not stay

C. to not stay

D. not to stay

解析：本题的含义是你看起来很累，你最好不要很晚睡觉，had better后跟动词原形，否定结构在其后加not即可，故本题选B。