Introductory it as Subject
Pattern group 1: it V clauseThere are five patterns in this group, each consisting of it, the verb, and a type of clause:
1.1 it V thatIt seemed that I was right.
1.2 it V to-infIt helps to talk.
1.3 it V whIt doesn't matter what you think.
1.4 it V when/ifIt hurts when you forget to write.
1.5 it V as if/as though/likeIt sounds as if they made a dreadful mistake.