4. Post Reading Lead-in Passage A Passage B Important sentences

6. B B. aim D. method A. result C. conclusion D A C Put these words in the correct order to describe the stages of a scientific experiment.

7. Read the passage and choose the best title for it. The Different Uses of Metals The Reaction of Metals The Reaction of Metals with Oxygen

8. MetalsHeated in oxygen Reaction with water or steam Potassium Burn to form an oxide Reacting with cold water Sodium Calcium Magnesium Reacting with steam Aluminium Zinc IronReacts slowlyPartial reaction CopperPartial reactionNo reaction The Reaction of Metals

9. Read the passage again. Answer these questions. 1. Which of the metals in the table reacts the most with oxygen and water? Potassium, calcium and sodium. 2. What happens when you heat calcium in oxygen? It burns to form an oxide.

10. 3. Which metals react with steam? Magnesium, aluminium and zinc. 4. Does iron have a slow or fast reaction with steam? It has a slow reaction. 5. Does copper react with water? No, it doesn’t.

11. What experiment does Passage B show us in? A. How does the nail rust? B. How does iron react with air and with water? C. How do we do an experiment about the reaction of iron?

12. Read the passage and fill in the table. Iron in dry air Iron in air-free water Iron in ordinary water Stage A (starting experiment) cotton wool water

13. Stage B (1 week later) Stage C (Result) nails water Iron does not rust Iron does not rust Iron rusts

14. 1. In the first part of the experiment, the ___ is dry, not wet. 2. It shows that iron ___________ when the air is dry. 3. In the second part of the experiment, you must ____ the water to make sure there is no ___ in it. air does not rust boil air Read the passage again. Complete the sentences.

15. 4. You add ________ to the water because this keeps ___ out of it. 5. It shows that ____ does not rust in water that has no ___ in it. some oil air nail air

16. 1. When we use metals, it is important to know how they react with different substances, for example, water and oxygen. = When we use metals, we should know how metals react with different substances, for example, water and oxygen, which is very important.

17. 本句是一个复合句，其中 when 引导时间 状语从句；在主句中， it 为形式主语， 真正的主语是动词不定式短语 to know... substances ，其中 how... substances 为 how 引导的宾语从句，作 know 的宾语， for example 引出同位语，表示举例。

18. 2. Here is a table with the metals that react most at the top, and the metals that react least at the bottom. = A table is here. At the top of the table we can see the metals that react most and at the bottom of the table we can see metals that react least.

19. 本句使用了倒装语序。句子的主语是 a table ，后面的 with... bottom 作定语修 饰 a table ；两个 that 都引导定语从句修 饰 the metals 。 句意 : 这里有一个表格，反应最强烈的 金属在最上面, 反应最弱的在最下面。