1、doing an experimenttongs crucibledissolvesolid / liquid / gasbalanceBunsen burnertest tube1. (a) Water exists as a solid, a liquid and a gas. (b) Water exists as a solid and a liquid only.2. (a) When you heat a metal, it expands. (b) When you heat a metal, it contracts.Guess, listen and check the an

2、swer. 3. (a) Steel is a mixture of iron and other substances. (b) Steel is a mixture of iron and oxygen.4. (a) Two-thirds of the earths surface is water. (b) 50% of the earths surface is water.5. (a) The distance of the sun from the earth is 25,5000 kilometers. (b) The distance of the sun from the e

3、arth is 150,500,500 kilometers.6. (a) The earth is 4.6 million years old. (b) The earth is 4.6 billion years old.7. (a) The earth is twice as large as the moon. (b) The earth is forty-nine times larger than the moon.Put the words in pairs or groups.air gas - oxygencontract - expandearth sun - moonga

4、s liquid - solidcontract air earth gas liquid oxygen moon solid sun expandAnswer these questions.1. Which of the above are natural? Electricity, iron, some metals and air are natural. 2. Which are man-made? Steel, some metals and glass are man-made. electricity iron metal steel air glass 3. Which ca

5、n be both? Electricity and some metals (alloys for example) can be man-made and occur naturally.1. When you heat a metal, it expands. expand vi. 膨脹，擴張膨脹，擴張e.g. The petals of many flowers expand in the sunshine. 許多花的花瓣在陽光中綻放。許多花的花瓣在陽光中綻放。反義詞反義詞contract vi. 收縮收縮 n. 合同合同e.g. The heat contracted the woo

6、len sweeter. 高溫讓羊毛衣縮小了。高溫讓羊毛衣縮小了。 Im under contract to teach here for one year. 我按照聘約要在這里教一年書。我按照聘約要在這里教一年書。2. Steel is a mixture of iron and other substances. mixture n. 混合物混合物e.g. The mixture of drinks made me feel bad. 我喝了混合飲料后很難受。我喝了混合飲料后很難受。 mix v. 混合混合 mix A with Bsubstance n. 物質物質e.g. Beware of what you do