If it 55 carefully planned,watching TV can be good for children.

问题描述:

If it 55 carefully planned,watching TV can be good for children.
55.A.are B.will be C.was D.is
为什么用is,不用will be
还有在一本情景剧中的介词用什么

条件状语从句,用一般现在时态表示将来的条件.