单选题What is the primary purpose of this passage?A To alert people to the dangers posed by the sun.B To discuss conditions on earth in the far future.C To present a theory about red giant stars.D To describe changes that the sun will go through.

题目
单选题
What is the primary purpose of this passage?
A

To alert people to the dangers posed by the sun.

B

To discuss conditions on earth in the far future.

C

To present a theory about red giant stars.

D

To describe changes that the sun will go through.


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参考答案和解析
正确答案: D
解析:
主旨题。本文主要谈论了目前作为一个黄色矮星的太阳会逐渐变成红色的巨星,白色的矮星,最终会成为一个黑色矮星。由此得知本文主要目的是谈论太阳所要经历的变化,因此选项D为正确答案。