In the lab

教学目标　　
　　1.owledge: words and useful expressions
　　First of all, once, unless, cupboard electricity turn off, shut, by the side of, soap, taste, oil, mix, mixture, rather, finger, instead of, second (n) , on holiday, message, proper Allow, experiment, basin, finally, lively, sadly, request, Petrol, castor, vinegar, dip, suck
　　2. Moral Education: To get the students to do everything as carefully as they can.
　　3.Emotional Education:
　　To supply the students with a very harmonious atmosphere in order that they can have a successful understanding of the text and discussion.
　　Main Points: To let the students master and use freely some of the useful everyday English.
　　1. Here are some dos and don'ts.2. Follow the instructions.
　　3. What /How about when we leave?4. Make sure that ......
　　5. Do what he or she tells you to do.6. Please tidy the lab.
　　7. Could you please show me how to use the computer?
　　8. Don't touch anything.
　　Difficult Points:
　　1.To encourage the students to discuss and then ask them to demonstrate their ideas by using the imperative sentence structure.
　　2. To review and master the sentence structure of Direct and Indirect Speech.
　　3.once / unless / as连接的主从句

教学建议

　　Since the dialogue and the text of this unit are about chemistry, the teacher may ask some questions about chemistry or other subjects to lead in the dialogue and then show the students the tolls that are used in the chemistry lab when the text is taught.
　　And also in order to make the class very lively and interesting the teacher may borrow the tubes which are filled with three kinds of liquids from the chemistry lab and ask them to guess what's in the tubes and then ask them to watch the teacher carefully then do what the teacher .
　　Does, which is the content of the text. In this case the students may feel very new and they may be interested in English class.
　　In order not to cause something dangerous to happen, the teacher may fill some white vinegar（白醋, some cooking oil(香油),some alcohol(白酒) in the tubes.
重点词汇讲解
1. first of all means first. 意为首先，第一
First of all, I want to say I'm very happy to be here with You.
First of all, we must make a decision.
相关的词组：at first which is opposite to "at last " for the first time 第一次
2．allow 的用法
allow + noun.
allow sb. to do / not to do sth../sb. is allowed to do
allow +doing
(1) He allowed no noise here.
(2) He allowed his boy to spend the weekend with his friends.
(3) Why did you allow her to smoke here?
(4) We don't allow drinking at school.
3. once 是连词，作“ 一旦……就……”讲。
(1) Once she arrives, we can start.
(2) Once you realize it, you will study hard.
(3) Once seen, it can never be forgotten.只要见过一次就难以忘怀。
注意once 一般和现在时连用。
4.unless是连词，相当于if …… not ……
(1) He will not come unless his homework is finished. == He will come if his homework is finished.
(2)You will be in trouble unless you follow my instruction. == You will not in trouble if you follow my instruction.
unless 和 not …until 的区别
unless 引导从句时多强调条件，而not …… until 句型则强调时间。Unless 连接的主从句的时态一般是主句是将来时而从句现在时。not …… until 连接的主从句中可以使用多种时态。
比较：
(1) You will fail in the exam unless you listen to the teacher carefully in class.
(2) We won't start until Bob comes.
(3) He didn't find out what had happened until his wife told him about it.
5. Don't touch anything unless your teacher tells you to do.
在此句末的to后省略了touch。在英语里，有些动词像hope, like, want, try, need, 助动词如be able to., be going to之后，为了避免前后重复，往往只用一个to代表动词不定式。
(1) You can go with me if you'd like to.
(2) You may stay at home if you want to.
(3) I don't want to go there, but he's going to.
6. What about when we leave?
What about ……?与How about ……?可以用来询问消息、提出建议或征询意见，其后可接名词、代词、动名词、副词（如next）和状语从句等。
(1) I'm ready. What about you?
(2) What about playing football?
(3) What about today's match?
7. make sure后跟了一个省略了that 的从句。当表示“ 弄确实、使确定”意思时， 常用在祈使句中，其后的从句里要用一般现在时。当make sure 表示“认为、确信”的意思时，其后的从句时态可视情况而定。
(1) Make sure (that ) you come early tomorrow.
(2) Make sure ( that ) your room is clean.
(3) We made sure you were not coming today.我们认为你今天一定不来了。
8.turn off 其反义词是“turn on "
turn up (开大) 其反义词是turn down (关小)
9.at the end of / in the end
at the end of 意为“ 在……末，在……尽头”，既可以表示时间的概念也可以表示空间的概念。而in the end只能表示时间的概念,其后不能接of短语，相当于 finally, at last.
(1) At the end of this term we will have a final examination.
(2) He died in the end though the doctors tried their best.
(3) There is a hospital at the end of this road.
10. with表示“ 具有，带有 ”
(1) China is a country with a splendid culture and a long history.
(2) Mr. Smith is a man with two sons.
(3) I live in a house with two windows.
11.You must do everything as I do.
as为连词，表示方式，意思是“按照、如同”
(1) State the facts as they are. 要如实地陈述事实。