介绍发明

话题分析

本单元的话题是“发明”，与此相关的写作任务是能简单介绍某项发明的历史、用途、特点等。写作时，文章要有条理性，语言要准确简明，能正确运用一般过去时的被动语态。

范文：

My invention is a flying bike.It was made last week. I think it's really such a great invention".Here is my introduction to it.It has two wheels and two wings so that we can use it to ride on the ground or fly in the sky.Besides,when we ride the bike,we can take photos or call others with it. What's more,it can not only travel very fast but also ：help to protect the environment and save energy because we use solar power to move it.

It has many advantages.However,it can be improved as well. First of all, we had better add so mething to the bike to stop us from falling1 off it. In addition, it's a good idea to set@ an u mbrella on it to help us keep off the rain.