—Oh my god! You wear slippers to attend the conference —Im sorry I forgot there is a con

问题补充：

—Oh my god! You wear slippers to attend the conference．

—Im sorry I forgot there is a conference．

A. must

B. can

C. should

D. shall

答案：

A. must

B. can

(答案→)C. should

D. shall

解析：（考查情态动词，在这里的意思是“竟然”。第一句的句意为：天哪，你竟然穿拖鞋来开会。）