Yana: I just don’t understand. We used to fish here all the time as kids, and we always caught a lot of fish. We’ve been here three hours and haven’t caught a single fish.

Brandy: Two words: acid rain. The water in the lake is probably acidic from acid rain, and many types of fish are not able to survive in acidic water. Before long, acid rain may wipe outmost of the fish in this lake.

Yana: So the acid rain is decreasing the biodiversity within the lake’s ecosystem.

Brandy: Yes. As the lake becomes more acidic, the numbers and types of fish, plants and animals that live in the lake decrease.

Yana: And there’s nothing we can do about it?

Brandy: Well, to reduce acid rain, we can clean up the oil and coal power plants that cause it or use more renewable resources, such as solar power and wind power.

词语解释（程度较高的读者也可以选择听对话词语的英文解释）

Acid rain：酸雨，即含有危险化学物质——燃烧矿物燃料产生的含硫烟尘——的降雨，伤害树木、庄稼、建筑物、以及湖泊溪流中的鱼类

To wipe out ：全部消灭

Biodiversity ：生物多样化

An ecosystem：一种生态系统，即存在于某一自然环境中的全部生命体（如动植物）和非生命体（如石头、土壤、阳光、水）

Reduce：减少，在谈环境时常指减少使用某种东西或资源。

A renewable resource：再生资源，即取之不尽或者可以自然再生的资源，如太阳能和风能

Solar power ：太阳能，即来自阳光的能量

Wind power：风能 ，即通过空气流动产生的能量

American English 网站提供可供英语学生和教师免费使用的多种英语资源。American English Facebook网页提供每天更新的英语学习资料。

Brandy: Two words: acid rain. The water in the lake is probably acidic from acid rain, and many types of fish are not able to survive in acidic water. Before long, acid rain may wipe outmost of the fish in this lake.

Yana: So the acid rain is decreasing the biodiversity within the lake’s ecosystem.

Brandy: Yes. As the lake becomes more acidic, the numbers and types of fish, plants and animals that live in the lake decrease.

Yana: And there’s nothing we can do about it?

Brandy: Well, to reduce acid rain, we can clean up the oil and coal power plants that cause it or use more renewable resources, such as solar power and wind power.

Now let’s review the vocabulary

Acid rain is rain that contains dangerous chemicals (due to smoke from burning fossil fuels that contain sulfur) and that damages trees, crops, buildings, fish in lakes and streams, and other things.

To wipe out means to destroy something completely.

Biodiversity is the different kinds of plants and animals that exist in an environment. It is the variety of life.

An ecosystem is everything that exists in a particular environment, including living things, such as plants and animals, and things that are not living, such as rocks, soil, sunlight and water.

Reduce means to make something smaller or to decrease. In environmental contexts, it often means to use less of something or to use fewer resources.

A renewable resource is a resource that comes from things that will not run out or that is naturally replenished, such as solar power or wind power.

Solar power is energy that comes from the sun.

Wind power is energy that comes from the movement of air.

The American English website offers a variety of free resources for learners and teachers of English. The American English Facebook page posts learning materials for English-language learners daily.

Everyday Conversations are developed by the State Department’s Heidi Howland, a senior program officer in the Office of English Language Programs, Bureau of Educational and Cultural Affairs.