初生演替和次生演替的主要区别是（）                         

如图表示人在吸气、呼气时胸廓上径、膈、肺的变化，依图回答下列问题：

    WeChat is a part of our daily life. We can chat with friends, share our photos on Moments and kill time by reading WeChat public accounts. And now, we can even gain new knowledge in WeChat study groups. Some teachers assign (布置) homework on WeChat groups or through other learning software. Song Xueying, a 16-year-old girl from Zhejiang province thinks that online homework makes our life more convenient because students are able to hand in their homework any time and anywhere. Hao Xiangjie, Song's classmate argues that online homework can do harm to students. This is because they are too young to get rid of the temptation (诱惑) of the Internet.

【写作内容】

1）用约30个单词写出上文概要；

2）用约120个单词阐述你对"利用微信群布置和完成作业"这一做法的看法，并用2 ~3个理由或论据支撑你的看法。

【写作要求】

1）写作过程中不能直接引用原文语句；

2）作文中不能出现真实姓名和学校名称；

3）不必写标题。