在初中英语教材中，出现了许多由it引导的固定句式，现归纳如下： 一、It's time for sb. to do sth. / It's time for sth.意为是(某人)该干……的时间了、到……的时候了。例如： 1. It's time for supper ／to have supper.该吃晚饭了。 2. It's time for me to study.我该学习了。 二、It takes(sb.)some time to do sth.意为(某人)花……时间做某事。例如： 1. It takes twenty minutes to go to school by bike. 骑自行车上学要花二十分钟的时间。 2. It took me a week to finish reading the book. 我花了一周时间读完这本书。 三、It is one's turn to do sth.意为轮到某人做某事了。例如： It's your turn to be on duty tomorrow. 明天轮到你值日了。 四、It is ／ has been ＋时间段＋since ＋一般过去时，意为自从……以来已过了……(时间)。 例如： 1. It is / has been four days since I caught a cold. 我感冒已四天了。 2. It is / has been two weeks since we met last. 自从我们上次见面以来已过了两周。 五、It seems ／seemed ＋that从句，意为看起来好像……。例如： It seemed that our team was going to win. 我们队看起来好像要赢了。 六、It's＋表语＋to do sth.。例如： It's a good idea to go out for a walk. 出去散步是个好主意。 七、It's ＋adj.＋that从句。例如： It's true that I may fall behind the other students.我真可能落在别的学生后面。 八、 It's＋adj.＋of(for)sb.＋to do sth.。对于这个句型究竟用of还是用for，主要取决于前面的形容词。如果形容词是描述不定式行为者的性格、品质等的，如 kind，good，nice，clever等用of；如果形容词仅仅是描述行为的则用for，这类形容词常见的有difficult，easy，hard， important，dangerous等。例如： 1. It is nice of you to come to see me.你能来看我真好。 2. It is dangerous for children to play with fire.对小孩儿来说玩火是危险的。
