下列说法正确的是（ ） A．3x2与ax2是同类项 B．6与x是同类项 C．3x
题型：选择题
问题：
下列说法正确的是（ ）
A．3x2与ax2是同类项
B．6与x是同类项
C．3x3y2与-3x3y2是同类项
D．2x2y3与-2x3y2是同类项
题型：选择题
阅读下列短文，然后按短文后的要求完成所给出的题目。
根据短文内容完成句子。
1. If you are in space, you can see ________ sunrises and sunsets in a whole day.
2. Some astronauts think ________ is the most fun thing to do during their free time.
3. Astronauts have to attach their sleeping bag to the wall, or they will ________.
4. Astronauts often ________ during their free time.
5. 将文中划线的句子翻译成汉语。