人教版八年级下册Unit6 An old man tried to move the mountains.Grammar 讲义

八年级下册英语人教版
Unit 6 An old man tried to move the mountains.
语法讲解讲义
八年级下册Unit 6 的重点语法为unless，as soon as 以及so...that的用法，在课文中多次体现，如：① But unless he can hide his tail, he cannot turn himself into a man. ②And as soon as the TV program came out more than 40 years ago, Western children became interesting in reading this story because the clever Monkey King keeps fighting to help the weak and never gives up. 等。
由于unless 和 as soon as 分别引导条件状语从句和时间状语从句，在时态上符合的规则与if 条件句相同，且unless=if not，所以在讲解时，咱们可以从if条件句的用法开始。
If的用法（引导条件状语从句）
主将从现
Eg. He will call me if he arrives in Hong Kong.
主情从现
Eg. You should eat something if you feel hungry.
主祈从现
Eg. Please let me know if he comes back.
注意：
① 若if条件句放在句首，从句后边要加逗号。
Eg. If he arrives in Hong Kong, he will call me.
② 如果谈论的是某一个动作发生后势必会产生某个结果，那么主从句都用一般现在时态。（事实）
Eg. If you boil water, it becomes steam.
例题：If you put wood into water, it __________ (float).
KEY: floats
Unless 除非，如果不 = if not （引导条件状语从句）
主将从现
Eg. We will go hiking unless it rains tomorrow.
主情从现
Eg. We won’t be able to go unless he comes.
主祈从现
Eg. Don’t come in unless you are invited.
As soon as 一.......就 （引导时间状语从句）
未发生的事情，符合主将从现，主情从现，主祈从现。
Eg. I’ll tell him the plan as soon as I see him.
发生过的事情，符合主过（一般为一般过去式）从过（过去的某一时态）。
Eg. The phone rang as soon as he got home.
总结：主将从现只适用于条件状语从句以及时间状语从句。
So... that 如此...以至于 （so是副词，修饰形容词或副词，that引导结果状语从句）
Eg. The teacher speaks so fast that I can’t catch the words.
区分：so that 以便，结果（引导目的状语从句和结果状语从句）
目的：I’m going to take an early bus so that I’ll get there in time.
结果：I took an early bus so that I got there in time.
课后练习：
______it rains, I’ll go to school by bus.
I will tell you the secret _____ you don’t tell anyone else about it.
The elephant has ______ strong a body ______it can do heavy work.
The mice knew that _________ they helped her make a dress, she would not be able to go to the party.
____________ her father died, the stepsisters made her do all the chores.
KEYS：1. If 2. If 3. so that 4. unless 5. As soon as