It引导的被动句
句型［It+被动式谓语+名词/形容词+实际主语（不定式、动名词）+其他］
1. It was considered a shame to cheat in examination. 2. It was found difficult for us to understand him.
3. It would be considered unwise your going there without a guide.
4. It was deemed sheer waste of time arguing about it. 5. It was proved wrong to say things like that.
句型［It+被动式谓语+实际主语（that/疑问关联词）+从句］
1. It is requested that you kindly take immediate action in the matter.
2. It was arranged that all the boys should go by bike and all the girls on foot.
3. It has not been found out who set the record.
4. It hasn't been made clear when the new road is open to traffic.
5. Has it been decided where we are to hold the conference?