It worries the couple ____ their daughter is eating less and less these days

题目

It worries the couple ____ their daughter is eating less and less these days
A how B when C that D where
请详细分析每个选项,
我想问为什么不是D呢
不好意思D是beceuse

答案

这句话实际上是以it作为形式主语,后面用that来引导主语从句——their daughter is eating less and less these days.
别的都不对,主语从句只能由that引导,所以也不必一一分析了.
此处如果用because的话前面的“It”就不知所云了.