unit38it做形式主语的用法.pptVIP

二. It 用作形式主语 当不定式（短语）、动名词（短语）或从句在某个句子中作主语时，为保持句子结构前后平衡，避免头重脚轻，因此常用it作形式主语置于句首，而将真正的主语放在句尾。此时it只起先行引导作用，本身无词义。 1. It + be + 形容词 + （for sb.）+ 动词不定式 这类句型常用形容词easy, difficult, hard, important, possible，wise等作表语，有时候为了强调不定式动作的执行者，常在不定式前加for sb，译为“对某人来说做某事怎么样”如： It’s necessary for the young to master two foreign language. It is unwise to give the children whatever they want. 2. It + be + 形容词 + of sb. + 动词不定式 这类形容词常是表示心理品质,性格特征的形容词，如：kind, nice stupid, clever, foolish, polite, impolite, silly, selfish, considerate等。某人和这些形容词可以构成主系表结构。如： It’s very kind of you to help me with the work. =You are kind to help me. It seemed selfish of him not to share his dictionary with others. =He seemed selfish not to share his dictionary with others. 3. It + be +名词词组 + 动词不定式，如： It is not a good habit to stay up too late. 5. It + take ( sb. )+ 时间（金钱）+ 动词不定式，译为，做某事花了某人多长时间或多少钱。如： It took the workers almost three years to finish building the dam. It will take a whole day to get to the top of the mountain on foot. 1. In fact is a hard job for the police to keep order in an important football match. A. this B. that C. there D. it 2. is a fact that English is being accepted as an international language. A. There B. This C. That D. It 3. Is necessary to take off our shoes when we enter the lab? A. everyone B. this C. her D. it 4. _____ will take you a lot of time to find him in the crowd. A. It B. I C. We D. They 5. It is no use his _________ there, the situation is hopeless now. A. to go B. to be going C. going D. having gone 6. Is _______ necessary to complete the design before National Day? A. this B. that C. it D. he 7. Does _______ matter if he can’t finish the job on time? A. this B. that C. he D. it 8、It is no __ arguing with Bill because he will never change his mind. A.