— Mary,how did your maths test go?

—I had thought I _____ ,but in fact I came in the top 10 in my class. 

A．should have failed

B．couldn’t have failed

C．might have failed

D．shouldn’t have failed

对新发现的肺结核未伴空洞形成的患者，首选用药方案是（）。

A.异烟肼+利福平+链霉素

B.异烟肼+链霉素

C.异烟肼+利福平+吡嗪酰胺

D.异烟肼+利福平+乙胺丁醇

E.异烟肼+吡嗪酰胺+乙胺丁醇