【单选题】听力原文: The origin of Earth's moon, the largest moon in the solar system, is still something of a mystery. There are some theories about its origin however. Now, keep in mind that a theory of the moon's...
A.
Differences between the planets in the solar system.
B.
Methods of determining the composition of Earth and the Moon.
C.
Why Earth has an iron core.
D.
The origin of the Moon.
【单选题】听力原文: The origin of Earth's moon, the largest moon in the solar system, is still something of a mystery. There are some theories about its origin however. Now, keep in mind that a theory of the moon's...
B.
In an astronomy class.
【单选题】内容提供者的 Uri 形式的组成部分有()
【简答题】二极管P区对应的电极叫做(),N区对应的电极叫做()。