(1) It is ＋ 名词 ＋ 从句

   It is a fact/an honour ---  that  +陈述语气从句

例：It is a fact that the earth moves around the sun. 地球围绕太阳转是事实。

    It is a pity/shame/no wonder that  + 虚拟语气从句

例：It is a pity that he should not come. 他若不来可真是遗憾。  

(2) It is ＋ 形容词 ＋ 从句

   It is natural/important/necessary/strange that + 虚拟语气从句

例：It is important that enough money be collected to fund the project.

    重要的是募集足够的钱，为这个项目提供资金。

   It is obvious/apparent/clear that  + 陈述语气从句

例：It is clear that she doesn't like the dress at all. 这很清楚她一点儿也不喜欢这条裙子。

(3) It ＋ 过去分词 ＋ 从句

   It is generally/commonly believed /accepted/thought/held that + 陈述语气从句

例：It is universally acknowledged that trees are indispensable to us.

　  全世界都知道树木对我们是不可或缺的。

    It is suggested/ordered/desired/requested/decided that +虚拟语气从句

例：It is suggested that we should hold a meeting next week. 建议我们下周开上会。