Introductory it as Object
Pattern group 4: V it n clauseThere are three patterns in this group, each consisting of the verb, it, a noun group, and a type of clause.
4.1 V it n thatI thought it a pity that she didn't get the job.
4.2 V it n to-infThey felt it their duty to visit her in hospital.
4.3 V it n when/ifI'd consider it a compliment if you accepted.