there are many people downstairs .what do you think ____ Ato happen B happening Cis happened Dhas
问题描述：
there are many people downstairs .what do you think ____ Ato happen B happening Cis happened Dhas
答
D has happened
do you think 是插入语.可以拿掉不影响句子结构.
故A项结构不完整,B项少了is C项错误,happen无被动
选D what has happened 发生了什么