7. Although the sea breaks up the waste, beaches may become polluted and fish may not be safe to eat. (L.22)

　　break up打碎;拆散;分解;break down(车辆、机器)损坏;(计划、谈判)失败;(身体、精神)崩溃;break out(战争、灾害)突然爆发;break in打断(谈话);突然闯入;break into破门而入;break away from摆脱(束缚);克服(习惯);脱离(政府)。 
如:

　　A large piece of ice broke away from the main block.

　　一大块冰从整个大冰块上断裂开来。

　　Chemicals in the body break our food down into useful substances.

　　人体中的化学元素把食物分解成有用的物质。

　　[高考示例]

　　News reports say peace talks between the two countries _____ with no agreement reached.

　　(NMET2003)

　　A. have broken out B. have broken down

　　C. have broken in D. have broken up

　　8. Second, much energy is wasted producing things that are thrown away. (L.22)

　　waste time (in) doing sth.意为“浪费时间做某事”,本句中介词in已省略。类似的结构还有:spend...(in) doing, be busy (in) doing, have trouble (in) doing等。如:

　　Graduates are busy (in) packing up for their working posts.

　　毕业生们正忙着整理行装去他们新的工作岗位。

　　[高考示例]

　　You’re _____ your time trying to persuade him; he’ll never join us. (NMET1995)

　　A. spending B. wasting

　　C. losing D. missing

　　9. At one time, certain types of radioactive waste were put in the sea in metal containers. (L.22)

　　at one time过去曾有一段时间;一度;at a time每次,一次;at the time目前;当时;at all times总是,一直;at times有时;at the same time同时;尽管如此;at no time 永不, 在任何时候都不;at any time随时; 无论何时。 如:

　　It seemed like a good idea at the time.

　　当时那好像是个好主意。

　　It will cost a lot of money. At the same time, I think we shall need it and it will certainly be useful.

　　它需要许多钱。然而,我认为我们将需要它;它一定会有用的。