Unit 4 Natural disasters第 3 课时 单元语法讲解栏目导航巩 固 习 题It 用法小结 一、it 用作代词，指代物，指前面提到过的同一事物；例如： Yesterday I bought a new bike and ___ was very expensive. You mustn’t play with knives. ___ is too dangerous. 二、it 也可指代人，一般指不明身份的人；例如： Whose baby may ___ be? Last midnight, someone broke into my room. ___ must be a thief. — Who is knocking at the door, Sarah? —___ may be Kate. I invited her here. it It it It It 三、it 作形式主语； 1．it 指时间、季节、天气、距离等；例如： ___ is 8:50． ___ is autumn now. ___ is raining cats and dogs outside. ___ is about a ten-minute ride from my home to the school. =___ is about ten minutes’ ride from my home to the school. It It It It It 2．用于固定句型 It is/was/will be+形容词+（for/of sb.）+to do sth.；例如： ___ is exciting to read comics. =Comics are exciting to read. ___ is warm-hearted of you to help me a lot. =You are warm-hearted to help me a lot. ___ must be very difficult for you to complete the work alone. =To complete the work alone must be very difficult for you. It It It 3．用于固定句型 It is no good（no use, no fun）doing sth. 或 It is（great）fun doing sth.，注意这里的 good，use 和 fun 都是名词；例如： ___ is great fun walking and cycling in Guilin. ___ is no good drinking too much alcohol. ___ is no use speaking loudly now. He is out. 4．用于句型 It is/has been+时间+since...（从句用一般过去式）；例如： ___ is two years since Kate left here. ___ has been two years since Kate left here. It It It It It 5．用于句型 It’s time to do sth. 或 It’s time for sth.；例如： ___ is time to have class now. =___ is time for class now. 6．用于句型 It takes/took/will take（sb.）to do sth.；例如：...
