来自世界不同地方的六位学生在美国相遇。他们都是交换学生，到美国大学就读一个学期，学习英语，了解美国文化，同时修专业课程。英语“日常会话” (Everyday Conversations)系列围绕这六位学生在美国的经历展开。这套材料适于中级或中级以上英语水平的学生使用。
三个学生（Akinyi, Lee and Peter）在一起欣赏Lee的旅行照片，其中有将风转化为电能的风力涡轮发电机的照片。三个人就此谈到风力发电的优越性。
Akinyi: Where were these pictures taken, Lee?
Lee: Which ones? Oh, those pictures are from a trip to the U.S. Botanic Garden. One of my classes went there to see the wind turbines.
Peter: There are wind turbines at the botanical garden?
Lee: It surprised me too. They’re small ones. Unfortunately, they only offset a small portion of the facility’s energy use. But putting small turbines on the rooftops of buildings is an interesting idea that is gaining popularity.
Akinyi: Interesting. But do they generate enough power to offset the cost of building them?
Peter: I really like how you’re always thinking like a businessperson!
Lee: No one knows for sure yet. It’s a fairly new endeavor in the wind energy field. At least now more people are looking at renewable energy.
Akinyi: This seems like a great field for entrepreneurs to enter. But it seems like the upfront costs would be huge, and the payback would take a long time.
Lee: Yes, that’s why some people think it’s important to have government subsidies to encourage clean energy use. But remember, the payback to society in the long run is huge!
让我们来学习一些词语（也可阅读英文解释）：
A wind turbine：风力涡轮发电机
A botanical garden：植物园
To offset：抵消
动词 generate 的意思是产生，带来
An endeavor：为达到某一目的而作的努力
Renewable energy：可再生能源 (“To replenish”：补充)
An entrepreneur：实业家，即创办企业并有准备为成功而承担风险的人
An upfront cost：预支费用。在这个对话中，“the upfront cost of purchasing the turbine”是指在能够从发电机发电获得收益前需要付出的购置发电机的成本。
Payback：回报。在这个对话中，“the payback of the turbine”指风力发电的成本低而且带来的是清洁能源。
A subsidy (复数: subsidies) 指政府或机构为降低某一产品或服务项目的费用而提供的补贴。
In the long run：长远的，最终的
有兴趣听更多英语对话吗？请浏览“英语学习”专题网页。
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。
“日常会话”由美国国务院教育与文化事务局英语语言项目处（Office of English Language Programs, Bureau of Educational and Cultural Affairs）资深项目官员海蒂·豪兰（Heidi Howland）编写。
