1、it + be + 名词 + that从句：it is a fact that 事实是。
it is an honour that 非常荣幸。
it is common knowledge that …是常识。
it is a pity that 遗憾…… 。
2、it + be + 动词的过去分词+ that从句。
it is said that 据说。
it is reported that 据报道。
it has been proved that 已经证明。
it is believed that … 人们认。
it is supposed that… 据猜测，
3、it + 不及物动词（vi） + that 从句。
it seems that 似乎。
it happened that 碰巧。
it appears that 似乎。
4、it is natural that… 很自然…。
it is strange that… 奇怪的是… 。