(共39张PPT)
Unit 7 Memory
Period 3 Grammar
牛津深圳·广州版八年级上册
Learning objectives
1.Knowledge objectives:
①Master the use of if conditional sentences to express the inevitable relationship between conditions and results.
②Students should master the transformation method between the conditional adverbial clause and the if... not structure guided by unless.
③Master the use of if conditional sentences to express the inevitable relationship between conditions and results.
Learning objectives
2.Skill objectives:
Students can complete the dialogue with if conditional sentences.
3.Emotional objectives:
Students can learn about the human brain and improve memory, develop a healthy lifestyle, find effective ways to improve memory, and maintain active thinking and memory.
4.Thinking capacity:
Cultivate students' ability to think and judge independently, summarize and express themselves.
Lead in
If the weather is fine, we will go
to the countryside tomorrow.
The following sentence is a conditional sentence guided by if. What does it mean What is the usage of the verb
Lead in
Let's look at the usage of if and unless conditional sentences.
Read the sentence below to review the use of conditional sentences.
If you make the picture big, strange or silly, you will remember it better.
the simple present tense
the simple future tense
Lead in
We have already learnt to use conditional sentences to talk about probable results.
If people eat too much, they ________.
Tom _______ miss the chance to go to the high school if he _______ the exams.
get fat
Look at the picture and plete the sentences.
Lead in
will
fails
If I’m ill, __________________.
I will see a doctor
If If I do something wrong,_______________.
I will say sorry
Look at the picture and plete the sentences.
Lead in
If it rains tomorrow, I_____________________.
’ll stay at home.
If it doesn't rain, I ___________________ tomorrow.
will go to the cinema
Lead in
If you heat water, ____________(蒸发).
The result will certainly happen,both verbs should be in the simple present tense.
Please fill in the blanks with the correct verb form.Find out the rules for using conditional verbs.
it evaporates
if you mix hydrogen and oxygen,_____________(你会得到水) .
a possible action
The result will certainly happen, both verbs should be in the simple present tense.
Grammar
you get water
If you switch off the light, ______________________(房间就会变暗).
the rooms becomes dark
the result that will certainly happen both verbs should be in the simple present tense.
If you put salt into water, ____________(它就会消失).
it disappears
a possible action
the result that will certainly happen both verbs should be in the simple present tense.
Grammar
Please fill in the blanks with the correct verb form.Find out the rules for using conditional verbs.
A Conditional sentences (2)
We have already learnt to use conditional sentences to talk about probable results.
We can also use conditional sentences to talk about results that will certainly happen.
Grammar
Rules
A1 Read these if-clauses and draw lines to match them with the results.
Practice
A2 In pairs, make conversations about the sentences in A1 on page 103. Follow the example.
Grammar
S1:What happens if you take a fish out ofwater
S2: It dies.
S1: Are you sure
S2: Of course, I'm sure, lfyou take a fish out of water, it dies.
S1: What happens if you switch off the lamp
S2: The room becomes dark.
S1: Are you sure
S2: Of course, I’m sure. If you switch off the lamp, the room becomes dark.
S1: What happens if you put wood into water
S2: It floats.
S1: Are you sure
S2: Of course, I’m sure. If you put wood into water, it floats.
Practice
S1: What happens if you take a fish out of water
S2: It dies.
S1: Are you sure
S2: Of course, I’m sure. If you take a fish out of water, It dies.
S1: What happens if you water a plant
S2: It grows.
S1: Are you sure
S2: Of course, I’m sure. If you you water a plant, it grows.
Practice
S1: What happens if you drop a glass
S2: It breaks.
S1: Are you sure
S2: Of course, I’m sure. If you drop a glass,It breaks.
Practice
Complete these sentences with the words in brackets.
If you ____ ice, __________ water. (turns/heat/it/into)
If you ____ steam, __________ water. (into/cool/turns/it)
Oil ___________________ water. (on/floats/pour/it/you/if)
Water ______________ it. (you/heat/boils/if)
heat
it turns into
cool
it turns into
floats if you pour it on
boils if you heat
Practice
The word unless can mean if ... not .
if... not and unless
The word unless can mean if ... not. For example, the two sentences below have the same meaning:
Grammar
unless的用法：意为“除非；如果不”，引导条件状语从句，相当于if...not，其引导的条件状语从句中的谓语动词常用一般现在时表将来。
Ex: Unless it rains tomorrow，we will go camping.
如果明天不下雨，我们将会野营。
Grammar
B1 Draw lines to match the beginning of the sentences in Column A
with the endings in Column B.
Practice
2 You will get a toothache if you do not brush your teeth every day.
________________________________________________________________________________________________________________________________________________
B2 Rewrite the following sentences with unless.
1 If you do not improve your handwriting, you will lose marks in the exam.
_________________________________________________________________________
_________________________________________________________________________
Unless you improve your handwriting, you will lose marks in the exam./
You will lose marks in the exam unless you improve your handwriting.
Unless you brush your teeth every day, you will get a toothache./
You will get a toothache unless you brush your teeth every day.
Practice
4. If you do not close that window, flies will get in.
_____________________________________________________________________
_____________________________________________________________________
3. This room will get very hot if you do not open the window.
______________________________________________________________________
______________________________________________________________________
Unless you open the window, this room will get very hot./
This room will get very hot unless you open the window.
Unless you close that window, flies will get in./
Flies will get in unless you close that window.
5. I will leave this restaurant if the waiter does not come soon.
_____________________________________________________________________
_____________________________________________________________________
Unless the waiter comes soon, I will leave this restaurant. /
I will leave this restaurant unless the waiter comes soon.
Practice
1. ___ you do ____ get enough sleep every night, you ________________ things well.
2. ______ you ____ enough sleep every night, you _______________ things well.
3. You _________ something very quickly ______ you __________ it well.
4. You _________ for school __ you ___________ now.
5. ______ you ________ your handwriting, ___________ marks in the exam.
not
If
will not remember
Unless
get
will not remember
will forget
unless
understand
will be late
if
do not leave
Unless
improve
you will lose
Fill in the blanks with if or unless.
Exercises
if引导的条件状语从句
一、概念
引导条件状语从句最常用的连词是if，常见的if条件状语从句表示在某条件下，某事很可能发生。当表示客观事实、结果时，if条件句的主句和从句都用一般现在时。
二、主从句的位置
if 从句可以放在句首，也可以放在句末。如果把 if 从句放在句首，常用逗号将其与主句隔开。如：Water turns into ice if the temperature is below zero.= If the temperature is below zero, water turns into ice.
summary
注意：if引导的条件状语从句通常不用一般将来时。在需要表达将来含义时，一般用现在时表示。
If从句(条件) 主句(结果)
一般现在时 一般现在时
If the temperature drops to zero degrees centigrade, water freezes.
If you pour oil on water, it floats.
记忆口诀：条件句表事实，主从句常用现在时。时态——“主现从现”。
三、主从句的时态
1.当表示客观事实、结果时，if条件句的主句和从句都用一般现在时。用来表达在该条
件下，结果一定会如此(如规则，客观规律、真理等)。结构是：If+主语+do/does，
主语+do/does。
summary
2. 当谈论将来可能出现的情况时，条件状语从句用一般现在时表示将来，主句常用一
般将来时。
If从句(条件) 主句(结果)
一般现在时 一般将来时
If it rains tomorrow, I won’t go out for a walk.
If you work hard, your dream will come true.
记忆口诀：谈论将来可能出现的情况。时态－－“主将从现”。
summary
3. 主句中含有情态动词(may/might/can/must/should)，if从句用一般现在时态。
If从句(条件) 主句(结果)
一般现在时 含情态动词may/might/can/must/should
If you finish your home work, you can go home now .
If it stops snowing, we can go out.
summary
3.主句为祈使句，if从句用一般现在时态。
If从句(条件) 主句(结果)
一般现在时 祈使句
If you are not strong enough, please don't take part in such an activity.
if you don't finish your homework, don' t play computer games..
summary
unless意为“除非”，和if…not(如果……不……)的意思相近在unless引导的从句里，通常用现在时表示将来。
例：I’ll not attend the party unless he invites me.
除非他邀请我，否则我不会参加这个派对。
Unless you have good idea, I’ll take his advice.
除非你有更好的主意，否则我将采取他的建议。
summary
unless从句的时态
注意：unless用于引出某事发生或成立所必需的条件。
例:You should not promise anything unless you can do it.
除非你能做到，否则不要随便许诺。
unless条件句，当所述条件会结束已经存在的想法，状态或趋向时，两个结构可以互换使用。
例：We shall go unless it rains tomorrow. =We shall go if it doesn’t rain tomorrow.
如果明天不下雨，我们就去。( “下雨” 会结束 “去” 这一已经存在的趋向)
例： They won’t come unless you say sorry.= If you don’t say sorry, they won’t come.
除非你道歉，否则他们不会来。
summary
unless和if…not 用法
Summary
条件状语从句:
if从句在某条件下，某事很可能发生。
unless“除非”，从句通常用现在时表示将来。
主将从现
主现从现
时态口诀:
将来出现的情况
客观事实;习惯
主情从现
主句含情态动词
主句含祈使句
主祈从现
if 引导的条件状语从句歌
if条件句不一般， 几个要点记心间。
条件句放在前， 逗号要放句中间。
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。
if条件句有特点， 现在时把将来替。
if是个连词，含义多多其中一个含义是“如果”，可以用来引导条件状语从句。if条件从句的主要用法可用下面的口诀来概括:
这个规则要牢记!
Summary
一. 根据汉语意思和括号内提示单词的适当形式填空。
1. 如果你再努力些，你将会通过考试。
If you _____(work) harder, you _________(pass) the exams.
2. 如果你请他帮忙，他将会帮助你。
If you _____(ask) him, he ________(help) you.
3. 如果明天不下雨，我们就去公园。
We _______(go) to the park if it ___________ (not rain) tomorrow.
4. 如果UFO降落在我面前，我将走进去 看看有没有外星人。
If a UFO ______(land) in front of me, I _______(go) in to it to look for aliens.
work
will pass
ask
will help
will go
doesn’t rain
lands
will go
Exercises
二. 根据括号内的提示，补充句子。
1. — I want to get high scores.
— If ______________________________(work hard/ do well)
2. — how can I remember my friends’ birthdays
— If_________________________________________ (keep a note in your diary / not forget).
3. — It’s late, but I don’t want to go to sleep.
— If ______________________________________________ (not get enough sleep/ feel tired at school).
you work hard, you will do well.
you keep a note in your diary, you won’t forget.
you don’t get enough sleep, you’ll feel tired at school.
Exercises
4. — I don’t like speaking English outside the classroom.
— If ____________________________________(not practice / not improve).
5. — Should I tell my teacher I don’t understand the homework
— If _____________________________________________ (not tell her / she not able to help you).
you don’t practice, you won’t improve
you don’t tell her, she won’t be able to help you.
Homework
Exercises
1.复习本节课所讲语法内容。
2.完成课后练习题。
