Ⅰ.单词拼写

　　1. The stone rolled down the mountain by gravity (重力).

　　2. The two continents were connected by a mass (块) of land at one time.

　　3. The_rainfall (降水量) averages 36 inches a year.

　　4. The radioactive (放射性的) waste should be buried deeply under the ground in sealed box.

　　5. When you left our space, you weren't in a fit state (状态).

　　6. They signed a treaty (条约) to settle all the border disputes.

　　7. Rivalry (竞争) with other schools is encouraged.

　　Ⅱ.拓展词汇

　　1. explorer n. 探险者→explore v. 探险；勘探→exploration n. 探险；勘探

　　2. annual adj.每年的→annually adv.一年一度地

　　3. depth n. 深度→deep adj.& adv.深的；深深地→deeply adv.强烈地；深刻地→deepen v. 加深；深化

　　4. inhospitable adj.荒凉的，不适宜居住的；不好客的→hospitable adj.好客的→hospitality n. 好客；殷勤招待

　　5. extreme adj. & n. 极端(的)，极度(的)→extremely adv.极端地，极其；非常

　　6. balance v. 使平衡→balanced adj.平衡的

　　7. commercial adj.商业的→commerce n. [U]商业，贸易，交易

　　8. promote vt.促进，增进→promotion n. 晋级； 增进

　　[巧记单词]

词根 词形变化 构词点拨 hospitable inhospitable in­加形容词构成具有否定意义的形容词 promote promotion 动词去e加­(t)ion构成名词 commerce commercial 去e加­ial构成形容词