Don't worry ,sir. I'm sure I can run () to catch up witn them .

问题描述:

Don't worry ,sir. I'm sure I can run () to catch up witn them .
A slowly enough B enough slowly C fast enough D enough fast

C (enough修饰形容词/副词时放在被修饰词的后面,故排除B与D.根据句意是‘跑得够快赶上他们,再排除A)