1、 1 / 5Chapter 1 语法 If 和 unless 引导的条件状语从句我们用 if 引导的条件状语从句来讨论可能的条件以及该条件成立时可能的结果。一. 学习 if 引导的条件状语从句的用法，我们可先从如下的口诀入手：If 条件句不一般，几个要点记心间；条件句，放在前，逗号要句中间条件句表可能，主句多用将来时；条件句表事实，主句常用现在时。We can walk there if we cant find a bus. 如果我们找不到公车，也能走路去那里主句 条件状语从句If it rains tomorrow, we will not go to the zoo. 如果明天下雨，我们
2、就不去动物园条件状语从句 主句What will you go if you find someone in danger? 主句 条件状语从句如果你发现某人有危险，你会怎么做？If 条件句有不同的类型，简述如下：1. 用 if 条件句表达客观真理或普通现象If 条件句用于表达客观真理或普通现象时，主，从句时态均用一般现在时，如：Eg. If you freeze water, it turns into ice.A fish dies if you take it out of water. 2. 用 if 条件句表示将来可能发生的事情在表示将来可能发生的事情的 if 条件句中，主句用一般将
3、来时，而 if 从句用一般现在时表示将来的时间，即主将从现 Eg. If I like the house, I will buy it. 如果我喜欢这房子，我就会把它买下I will tell her if I see her. 如果我见到她，我就会告诉她。主句中的 will 也可以用情态动词 can, may 或 might 等代替。如：Eg. If they are friendly，I might invite them to the party. 如果他们很友善，我可能会请他们去参加聚会2 / 5If we hurry now, we can stop for coffee late
4、r. 如果我们现在抓紧时间，就可以稍后去喝咖啡注意：在条件句中，主句部分只能使用动词 will 的一般将来时，不能使用 be going to 的结构二. Unless 的条件句表示在特定条件下，才决定做或不做一件事，中文用的连接词一般是“除非”和“否则” 。如：除非刮台风，否则演唱会将如期进行。在英语中，我们可以用unless 表达这个意思，相当于 if not。以这个句子为例：The concert will be held as schedule unless there is a typhoon.= the concert will be held as schedule if the
5、re is not a typhoonShe will keep on singing unless she is told to stop. 她会一直唱下去，除非有人叫她停止= she will keep on singing if she is not told to stop也可以用 or(否则) 来做同义句转换Unless you listen carefully, you wont know the answer. = if you dont listen carefully, you wont know the answer.= you should listen carefull
6、y, or you wont know the answer.3 / 5深圳中考题：1. If I _ his phone number, I will tell you.A. find B. found C. will find D. have found2. We will go camping if it _ tomorrow.A. Wont rain B. didnt rain C. doesnt rain D. isnt raining3. Im waiting for my friend. If he _, I _ swimming alone.A. doesnt come; wi
7、ll go B. wont come; will go C.will come; wont go D. dont come; will go4. _ you go to the supermarket at 7 p.m, you can buy a lot of cheap food.A. If B. Unless C. Whether D. When5. I wont get to the party on time _ I catch the first train tomorrow morning.A. If B. Unless C. Whether D. When6. -Shall w
8、e go on a picnic this weekend?-Good idea! Unless it _.A. rains B. doesnt rain C. rain D. wont rain7. -Can I change the jacket for another one _ it doesnt fit me well?- Of course.A. unless B. if C. that D. though8. Nobody can learn maths well he works hard on it.A if B unless C thought D however9. If
9、 fish away from water, they die.A are taking, wont B are taken, will C are being taken, will D take, wont10. Each student can ask teachers for help if he how to work out the problem.A will know B wont know C dont know D doesnt know4 / 5创 造 励 文 化 包 容 诚 信 笃 行 勤 奋 1 18926518344 83872250 一 A用 if或 unless
10、填 空 1. he wants to see me, you can tell him to wait. 2. it snows tomorrow, well have a day or two off. 3. We wont go to his party he invites us. 4. She is sure to pass the examination she is ill. 5. Ill take that computer I have enough money. 6. my grandma wears glasses, she can see better. 7. I won
11、t buy that backpack it costs less than $20 8. Im tired; Ill have a rest for tea. 9. You wont get paid for time off you have a doctors note. 10. you will get a toothache you do clean your teeth regularly. B 用 所 给 单 词 的 适 当 形 式 填 空 1. If he (get) a low mark in the test, he (study) harder. 2. If you (s
12、wim) every day this summer, you (be) very healthy. 3. If he (not hurry), he (not see) the beginning of the match. 4. You cant go out unless you (finish) your homework. 5. Unless I save my money carefully, I (not be) able to buy a football. 6. If it (not rain) tomorrow, we (go) to the park. 7. If he
13、(return) to the school, I (let) you know. 8. He smoking unless he (have) enough money. 9. They can remember it better if someone (give) them some advice about it. 10. The man (set off) if he (buy) the air ticket. 二 解 释 句 子 1. you will feel worse unless you take more rest. 2. you will be late for work if you dont hurry up. 3. no one is going to help you unless you change your mind. 5 / 5
