–You can’t imagine great fun chatting online is.– Really? But it may cause you a lot of t

问题补充：

–You can’t imagine great fun chatting online is.

– Really? But it may cause you a lot of trouble.

A. what

B. how

C. why

D. whether

答案：

(答案→)A. what

B. how

C. why

D. whether

解析：此题考查感叹句。imagine后是一个感叹句，又知fun是不可数名词，所以用what。句意：你不能想象出网上聊天是多么的有趣呀。所以选A。