宇宙中最基本的天体类型是 A．行星和卫星 B．恒星和星云 _爱下问搜题

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问题选择题

宇宙中最基本的天体类型是

A．行星和卫星

B．恒星和星云

C．彗星和卫星

D．行星和流星体

答案

B

题目分析：在宇宙空间的众多天体中，最基本的天体为恒星和星云；而行星、彗星和流星体等都是围绕恒星运动，卫星是围绕行星运动。故选B。

补全对话，情景问答

从方框中选择适当的句子补全对话，有两项是多余的。

A. I can speak Chinese.
B. I have two children.
C. I like teaching.
D. Are you all in the same school?
E. I work in a middle school near here.
F. I like Chinese people, too.
G. How many English lessons do you have every week?

A: Good morning! Where do you work?
B: 1_____ I'm a teacher.
A: What do you teach?
B: I teach English.
A: 2_____
B: Almost two lessons every day.
A: Do you like workingin China?
B: Yes, I do. 3_____
A: Do you have any children?
B: Yes, I do. 4_____
A: Are they studying here?
B: Yes, they are.
A: 5_____
B: No, we aren't They go to different schools.

填空题

声波在围护结构中的传递基本有空气和（）二种形式。