1. — ________it is to watch Xiao Shenyang’s performance!
—So it is！Everyone present will burst into laughter.
A. What a fun B. No wonder
C. No doubt D. What fun
解析：选D。考查交际用语。根据Everyone present will burst into laughter可知选D。fun是不可数名词，前面通常不用冠词。No wonder难怪；No doubt肯定地，想必。
