本单元的话题是“发明”，涉及科普知识与技术等内容，是学生最感兴趣的话题之一。写作体裁多为说明文，写好这类文章一定要抓住事物的特征、功能和用途。
写作此类话题作文的常用表达有：
(1)When was …invented?
(2)It was invented…
(3)They are used for…
【典型例题】
计算机在我们的生活、工作中的作用越来越大，你知道计算机的'起源与发展吗?请结合计算机的发明时间(1946年)、外形、用途等方面，谈一下它的发展变化，并说明你对未来计算机的畅想。
【优秀范文】
Computers are becoming more and more important in our daily life. Do you know when the computer was invented?
The computer was invented in 1946. At that time, it was huge. With the development of science and technology, the computer has grown smaller. Now there are many kinds of computers, such as personal computers and laptops. The computer is a very useful tool in our life. For example, it can send some messages to foreign friends by email. What’s more, it can share information with others through the World Wide Web. We can also listen to music or play the game on computers. It makes us relax.
It’s hard to imagine what our life would be like without computers. I think computers will be more convenient and they are going to change our life completely in the near future.
