What is in it?

题目

What is in it?
介宾in it作主语?what是表语?

答案

1.楼主理解有误.
2.in it是表语,而what是句子的主语.
3.可以把该句变成相应的陈述句来看：The book is in it.
如果该句对The book划线提问的话,刚好变成：
What is in it?