abundant medical aid that cloning could provide.

5. Explain some important words for Ss.

(1) happen vi (偶然地)发生；出现 Page11.line2 and page 12.line5

辨析：happen, befall, occur, take place与come about

happen, occur, befall, take place, come about五词都有"发生"之意，但有区别。

happen 使用最广，有偶然发生之意。

Befall 指灾祸等的发生或出现。多用于书面语，并且往往暗示命运的作用。

occur 用法较正式，既可以指自然发生，也可以指有意安排。可用于具体的事物，也可用于抽象的事物。用于指具体事物时，可与happen 互换（但happen 后接不定式时，不能与occur互换。该词有"想起"的意思，这时不可同happen互换

take place 常可与happen, occur互换 ( 以具体事物作主语时)，但较多地指有计划，按事先安排的进行的含义。引申用法可表示举行、进行的意思。

come about 往往注重事情发生的原因，常与how 连用。

注：以上五词均为不及物动词，无被动语态。

(2) disturbing (page 12 line2) 烦扰的

I`ve had some disturbing experience.

　● 拓展：disturb 打扰、使焦灼不安、扰乱

I'm sorry to have disturbed you.

The dream so disturbed him that he could not sleep.

A light wind distured the surface of the water.

(2) cast down (page12 line3)（多用于被动结构或作表语）沮丧，低沉，泄气

Anyone would be cast down by such news as that.

He seemed cast down as a result of his failure to find work.

He was very downcast when he got the exam results.

(3) raise (page 12 line8) 举起，使起来，唤起，提高，筹款，养育

● 拓展：rise vi 起立，升起，上涨，高耸，起义

Step 2. Consolidation.

Purpose: To consolidate the words and phrases in the text.

1. Ask Ss to complete the following sentences using suitable words or phrases

(1) Chinese ______ greatly _____ French in pronunciation.

(2) He ______ to finish the job by Friday.

(3) Many people ______ experimentation on animals.

(4) You are not legally ______ ______answer these questions.

(5) It took them three years to ______ ______ the debt.

(6) A new oil crisis has ______.

(7) Anyone would be______ ______ by news such as that.

Suggested Answers:

(1) differs... from (2) undertook (3) object to (4) bound to

　(5) pay off (6) arisen (7) cast down

2. Ask Ss to finish Ex3 on P13 and check the answers in pairs.

3. Ask Ss to fill in the brackets to complete the passage below. Then let some Ss present their