When he fell off the bike he tried but couldn't .A. to have stood upB. standing upC. to

问题补充：

When he fell off the bike, he tried but couldn .

A. to have stood up

B. standing up

C. to stand up

D. having stood up

答案：

A. to have stood up

B. standing up

(答案→)C. to stand up

D. having stood up

解析：fall off the bike意为: 从自行车上跌下来,try to do sth.意为：尽力做某事。