高三英语一轮复习---it用法课件(共37张PPT)

it用法 it用作主语 it指代事物、动物、婴儿或未知的人 What is this?--It is a book. Someone is at the door.--Who is it? Her new baby is tiny.It only weighs 2 kilos. 指代天气、时间、距离、季节、事物的状态和自然环境等 It is getting colder and colder. It is two years since I last saw you. It was very quiet in the cafe. How is it with Mr.Rose? It is only twenty minutes' drive to our college. it 作形式主语，代替不定式、动名词或从句，使原来的这些主语可以放在句子后面，避免句子头重脚轻。 1.it代替不定式作主语 It cost me $25 to buy the dictionary. Is it necessary to complete the design before National Day? It's a good idea to have a little note book handby. 注意：有时不定式前面有一个for引起的短语，表示不定式逻辑上的主语，用it作形式主语时，构成下面句型 It is+adj.+for sb.+to do 此句型中的形容词为静态形容词，即描写人或物的静态特征的形容词，用来表示客观情况。这样形容词有： easy,difficult, important,hard,necessary,essencial, impossible,dangerous,common,unusual,big, small,tall,long,short,wide,old,young,beautiful等 It is very difficut for me to learn Spanish. It is getting harder every day for a poor man to get a living. 注意：有时不定式前面有一个of引起的短语，表示不定式逻辑上的主语，用it作形式主语时，构成下面句型：It