长期应用糖皮质激素后,突然停药所产生的反跳现象是由于病人（）

A．对糖皮质激素产生耐药性

B．对糖皮质激素产生了依赖或病情未能完全控制

C．肾上腺皮质功能亢进

D．肾上腺皮质功能减退

E．ACTH分泌减少

So ________ student ________ that he can work out all difficult problems.

A．clever a ; was he

B．a clever; was he

C．clever a , he was

D．a clever, he was