It-is-+adj.-+动词不定式的用法

精品文档 1欢迎下载 It is adj 动词不定式的用法 I It is adj to do something 结构 句中 it 是形式主语 真正主语是动词不定式 to do something 因此也可以表达为 to do something is adj e g It is amazing to drive past fields which seem to go on forever or whole hills covered with neat rows of grapevines 本句形式主语为 it 真正主语 to drive grapevines 移到了句子后部 使句子变得 平稳 不致主语太长 如果把真正主语放在前面 那么整个句子就显得头重脚轻 因此 就用 it 作为先行主语 这种结构还有两种动词不定复合结构 1 It is adj for somebody to do something e g It was very difficult for them to fly because men have not got wings 此句真正的主语是动词不定复合结构 for them to fly 其中 them 是 to fly 的逻辑 主语 2 It is adj of somebody to do something e g It is sensible you to bring an umbrella in such weather A in B for C with D of 答案为 D 这里 sensible 跟逻辑主语 you 的关系是表达人的特点 性格 本质等 像 此类形容词还有 kind foolish clever wise friendly 等 II It is 名词 to do something 结构 e g It is great fun to see the pandas walking in the zoo III 另外 it 作先行主语时还有其他用法 1 it 及物动词 宾语 不定式 e g It cost me 100 dollars to repair the car It takes me two hours to finish my homework every day It gave me great pleasure to watch them 2 it be 名词 形容词 doing e g It is no use studying for an exam at the last minute It is a waste of time talking to him It is pleasant sitting here Exercise I Choice 1 Today it is easy on line and millions of people use the Internet everyday A get B to get C gets D got 2 It is clever you to answer such a question A for B on C with D of 3 fun it is to ride on a camel in the desert A What B What a 精品文档 2欢迎下载 C How D How a 4 It takes 3 days for the parcel America by air mail from Shanghai A reach B reached C to reach D reaches 5 important thing it is to do eye exercises everyday A What B What a C What an D How 6 It is no use about the school lunch A complain B complaining C to complain D complained II 用 it 作形式主语改写句子 1 To speak English more is very important for you 2 To do more exercises is very helpful 3 To do is more important than to say 4 To help others is our duty 5 To go to the South Pole is the boy s wish 6 To drink plenty of water is good Key