石油主要由元素（）和（）组成，其中碳含量83～87％，氢含量11～_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题填空题

石油主要由元素（）和（）组成，其中碳含量83～87％，氢含量11～14％，另外还含有少量硫、氮、氧。

答案

参考答案：碳、氢

补全对话，情景问答

根据对话内容，从方框内选择合适的句子补全对话。(有两项多余)

A. Who has gone there?
B. When are you going there?
C. I haven't been there, either.
D. I've seen and learnt a lot there.
E. What have you done for the holiday?
F. Which pavilion do you want to visit most?
G. But I hear there're a large number of people every day.

M: Yang Liu, the summer holiday is over. __1__
W: I have visited the World Expo Garden in Shanghai.
M: That must be exciting. __2__ You must have waited for a long time to visit some wonderful pavilions,
didn't you?
W: Yes, I did. But I think it's worth (值得) visiting. __3__
M: You're right. I want to go to the World Expo Garden, too.
W: __4__
M: I'm planning to go during National Day holiday.
W: __5__
M: The China Pavilion, of course.
W: Have a pleasant trip.
M: Thanks.

问答题简答题

为什么要使用放射性元素来检测料位？