There is a real possibility that these animals could be frightened,__B__ a sudden loud noise.

题目

There is a real possibility that these animals could be frightened,__B__ a sudden loud noise.
A.being there B.should there be C.there was D.there having
答案是第二项,可是不明白这里为什么选它,这是什么结构,那位帮帮我呀.

答案

虚拟语气 省略
完整的是
if there should be a sudden noise.
如果突然有一个很大的声音 动物们真的有可能被吓到