内容来源：分享美国 地址链接：http://go.usa.gov/cKrEm

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。

Audio: 
https://share.america.gov/wp-content/uploads/2015/12/DEC-W2-D3.mp3?_=1   Use Up/Down Arrow keys to increase or decrease volume.

Peter: I’m really glad you dragged me to that lecture, Lee. That was great. Now I want to make a lesson plan about this topic for young learners.

Lee: Wow, that’d be hard. Ocean acidification isn’t an easy topic to simplify for kids. Do you think you could do it?

Peter: I think so. It helps to get kids interested first. Start with things they already know about. For example, ask them, “Do you like corals, crabs, clams and fish?” Then, explain the process that is harming these things.

Lee: The process seems like it would be the hard part to explain to kids.

Peter: Maybe a little. Let’s see, how would I start? First, there are fossil fuel emissions. This produces carbon dioxide in our atmosphere. Over time, the oceans take in the carbon dioxide.

Lee: You really learned a lot today! I’m impressed. Okay, so now the oceans have a lot of carbon dioxide. Then what?

Peter: The increased carbon dioxide changes the chemistry — or, more simply, the structure — of the water. And that can have a bad effect on the marine ecosystem, such as harming corals, crabs, clams and fish.

Lee: That was pretty straightforward. Your future students are going to be lucky to have you as a teacher.

让我们来学习一些词语（也可阅读英文解释）：

To drag someone somewhere：拉着某个(不情愿的)人去某处

Ocean acidification：海洋酸化，指海水酸碱度降低，由空气中的二氧化碳增多导致海水中的二氧化碳浓度增加造成。

Fossil fuel emissions：矿物燃料排放，即煤炭、石油或天然气等燃料在燃烧时带来的二氧化碳排放

The Earth’s atmosphere：地球大气层

A marine ecosystem：海洋生态系统，包含存在于海洋环境中的一切物质，既含有生命的动植物，也包括无生命的岩石、泥沙和水。

有兴趣听更多英语对话吗？请浏览“英语学习”专题网页。.

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.