( )is very interesting to swim in the river,but it'sdangerous.Athis b that c it d he

问题描述:

( )is very interesting to swim in the river,but it'sdangerous.Athis b that c it d he

C
It is +adj.+ to do sth 固定用法

( )is very interesting to swim in the river,but it'sdangerous.Athis b that c it d he
Cit 这里做形式主语 to swim in the river才是真正主语

C

c it 做 形式 主语

答案 C it 形式主语,代之 to swim in the river