牛津版沪教版英语八年级(上)Unit7Memory语法讲解+练习+答案
Unit 7 Memory
语法讲解：条件状语从句，if…not=unless
由引导词if或unless引导的状语从句叫做条件状语从句。在英文中，条件是指某一件事情实现之后（状语从句中的动作），其它事情（主句中的动作）才能发生，通常译作“假如”。从句的位置可在主句之前或之后（从句在前，一般需要用逗号与主句分隔）。
一、if引导的条件状语从句
potato什么意思
actress条件状语从句最常用的引导词是if（连词）。
（1）主现从现
构成：主句（一般现在时态）+ if从句（一般现在时态）
用法：讲述自然规律，肯定会发生的事情或客观事实。例如：
If you take a fish out of water, it dies.如果把鱼从水中拿出，它会死。
If you put a piece of paper into water, it gets wet.如果你把一张纸放进水中，它会变湿。If you put salt into water, it disappears.如果你把盐放入水中，它会消失。If you heat ice, it turns into water.如果你加热冰块，它会变成水。reali和realize
Steam turns into water if you cool it.如果你冷却水蒸气，它会变成水。
Oil floats if you pour it on water.如果你把油倒入水中，它会漂浮。
（2）主将从现、主祈从现、主情从现
会计行政法规组成：主句（普通未来时态、祈使句、神态动词）+ if从句（普通目前时态）用法：评论未来大概会产生的情形。比方：
①I’ll buy a car if I have enough money.假如我有充足的钱，我会买一辆车。They won’t go out if it rains heavily tomorrow.假如明世界大雨，他们不会外出。②Be careful when you cross the road.过马路时要谨慎。
Put up your hand if you have any questions to ask.如果你们有问题要问的话，请举手。③If I get there early, I can e the doctor quickly.如果我早早地到那里，我就可以快点看病。You can get good grades if you study hard.如果你努力研究，你会取得好成绩。注：
if指导的前提状语从句，偶然还可由when，as soon as（一…就…），（not）…until（直到…才）等指导的工夫状语从句来交换。
出国留学文书写作I will go home as soon as it stops raining. =
I will go home if it stops raining.雨一停我就回家。
Pleadon’tleave the office until your friend comes back. =
Pleadon’tleave the office if your friend doesn’t come back.请不要离开直到你朋友回来。The traffic must stop when the lights are red. =
The traffic must stop if the lights are red.当红灯亮时，交通必需截止。
二、unless引导的条件状语从句
unless= if …not除非，假如不。例如：
Let's go out for a walk unless you are too tired. =
let's go out for a walk if you are not too tied. =
Unless you are too tired, let's go out for a walk. =
If you are not too tied, let's go out for a walk.
我们出去散步吧，除非你太累了。
You will fail to arrive there in time unless you start earlier. =
You will fail to arrive there in time if you don’t start earlier. =
Unless you start earlier, you will fail to arrive there in time. =
dutyfreeIf you don’t start earlier, you will fail to arrive there in time.
假如你不早点启碇，你就不克不及实时赶到那儿。
Unless it rains, the game will be played. =
If it doesn’t rain, the game will be played.=
The game will be played, unless it rains. =
The game will be played, if it doesn’t rain.
除非下雨，比赛将照常进行。
swap是什么意思My baby sister never cries unless she is hungry. =
欧美经典电影推荐My baby sister never cries if she isn’t hungry.=
Unless she is hungry, my baby sister never cries. =
If she isn’t hungry, my baby sister never cries.
我mm不会乱哭，除非她饿了。
Unit 7 Memory
语法练习
一．用if或unless填空
1. _________ he wants to e me, you can tell him to wait.
中国招生代理网2. _________ it snows tomorrow, we'll have a day or two off.
释怀的英文
