immediately.

根据上文判断正(T)误(F)

1．Students can work in the lab by themselves if a teacher isn't present.(F)

2．You can drink when thirsty，but you can't eat when hungry in the lab.(F)

3．You must never wear contact lenses in the lab.(F)

Period One　Introduction & Reading and Vocabulary

Ⅰ.重点单词

1．expand vi.膨胀

contract vi.收缩(反义词)

2．electricity n．电

electrical adj.与电有关的；用电的

3．conclusion n．结论

conclude v．断定；推断出；得出结论

4．aim n．目标；目的

5．reaction n．反应

react vi.(化学)反应

6．equipment n．设备；装备

equip vt.装备；配备

7．partial adj.部分的；局部的

8．ordinary adj.普通的；平常的

9．float vi.漂浮

10．form vi.形成

Ⅱ.重点短语

1．react with和......发生化学反应

2．at the top在顶部

3．at the bottom在底部

4．add...to...把......添加到......；往......加入......

5．keep...out of使......不进入；置身......之外

Ⅲ.重点句式

1．"分数/百分数＋of＋名词"作主语

Two-thirds of the earth's surface is(be) water.