常用的连接性副词主要有however, therefore, nevertheless, as a result, instead, thus, in contrast, similarly, for example, at the same time, on the other hand, consequently, in addition, furthermore等。

1. The zoos _____________________________________; ___________, they keep city people in closer contact with the more natural world.
动物园保护许多野生动物，此外，它们还使城市居民有机会接触到自然状态下的动物世界。

2. Cloning could be used to increase the population of _________________________ of animals and thus save them from total ______________.
克隆技术可能被用来增加濒危物种的数量，从而避免它们的灭绝。

3. Some people are using bicycles for transportation; ___________, others are ______________ or taking ________________ to get to their destinations.
有些人使用单车作为交通工具，还有些人合作使用汽车或搭乘公共交通工具去他们的目的地。

4. Intelligent machines such as robots can replace humans to do some dangerous tasks; ___________, they release housewives from ____________________________.
智能机器，如机器人，能代替人从事许多危险的工作，此外，它们也使家庭主妇从日常家务活中解脱出来。

5. The company produces poisonous gases day and night; _________________, ________________________________among residents nearby _________________.
那家公司整天制造出有毒气体，因此，附近居民患癌症的比例急剧上升。

本期题目：
请将题目中的空格填上。

答案:
1.conserve many forms of wildlife, furthermore

2.endangered species, extinction

3.moreover, joining carpools, public vehicles

4.in addition, daily household chores

5.consequently, the incidence of cancer, skyrockets