Introductory it as Object
Pattern group 5: V it adj clauseThere are three patterns in this group, each consisting of the verb, it, an adjective group, and a type of clause.
5.1 V it adj thatHe made it clear that he would not negotiate.
5.2 V it adj to-infI find it hard to understand your motives.
5.3 V it adj whHe left it unclear whether he would resign or not.
5.4 V it adj when/ifI think it best if you tell him the truth.