有时为避免句子头重脚轻,常用形式主语it代替主语从句作形式主语放于句首,而把主语从句置于句末。主语从句后的谓语动词一般用单数形式。常用句型如下: (1) It + be + 名词 + that从句It is common knowledge that 是常识It is a surprise that 令人惊奇的是 It is a fact that 事实是 (2)It + be + 形容词 + that从句It is necessary that 有必要 It is important that 重要的是 It is obvious that 很明显 (3)It + be + 动词的过去分词 + that从句 It is believed that 人们相信 It is known to all that 众所周知 It has been decided that 已决定 (4) It + 不及物动词 + that 从句 It appears that 似乎 It happens that 碰巧It occurred to me that 我突然想起另注意:在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时,谓语动词要用虚拟语气“(should) +do”,常用的句型有:It is necessary (important, natural, strange, etc.) thatIt is suggested (requested, proposed, desired, etc.) that |