B
To understand why the Earth is warming up, first of all, we need to understand why it is warm. Our planet is covered with atmosphere(大气层). Sunlight passes through the atmosphere and reaches the Earth. The Sun heats up the Earth's surface. When the heat rises into the air, it is stopped by some special gases in the atmosphere like $\mathrm{CO}_2$. The heat returns to the Earth and keeps it warm.
Power stations and cars release so many greenhouse gases every day. So we can help stop global warming by using less electric things such as turning off lights when we leave a room, asking our parents to turn down the heating in our house to save energy. We can also stop global warming by finding other ways of transportation. For example, ride a bicycle or walk instead of going by car. Another way to help stop global warming is to plant and care for trees, because trees take in $\mathrm{CO}_2$. They are our best friends when fighting against global warming.
The problem of global warming cannot be solved in a day. It may take a long time to find clean energy, such as wind energy. It may take a long time to plant the trees again. But every little thing each person can do to save energy and our forests will help reduce global warming. Think about our planet. Think about ways we can help make the Earth a safe and comfortable place for the future.
()1. The underlined word "it" means "" in the first paragraph.
A. the heat
B. the Earth
C. the sunlight
D. the atmosphere
()2. ways are mentioned to stop global warming according to the second paragraph.
A. Two
B. Three
C. Four
D. Five
()3. The underlined word "release" probably means "" in Chinese.
A. 压缩
B. 阻挡
C. 释放
D. 吸收
()4. Which of the following is NOT true?
A. Everybody can help save energy and our forests.
B. The problem of global warming cannot be solved.
C. To find clean energy will help solve the problem of global warming.
D. The writer wants us to pay attention to the problem of global warming.
()5. Which is the best title for this passage?
A. Why Is the Earth Warming Up?
B. When Can We Stop the Earth from Warming up?
C. How Can We Stop the Earth Getting Warmer?
D. How Long Will It Take to Stop the Earth Getting Warmer?

1.B 2.B 3.C 4.B 5.C

1. 定位原文第一段第一句"To understand why the Earth is warming up, first of all, we need to understand why it is warm."，结合句意可知这里的代词it指代前文提到的the Earth，对应选项B。
2. 通读第二段，文中一共提到了三种阻止全球变暖的方法：①减少用电、节约能源；②选择骑行、步行等低碳出行方式；③种植和爱护树木吸收二氧化碳，对应选项B。
3. 结合常识和语境，发电厂和汽车每天会向空气中排放温室气体，可推断划线单词release的中文含义是"释放"，对应选项C。
4. 细节判断：A选项符合原文最后一段"every little thing each person can do to save energy and our forests will help reduce global warming"的表述；C选项符合原文提到的开发清洁能源可以缓解变暖的内容；D选项符合作者呼吁大家关注全球变暖问题的写作意图；原文表述是"The problem of global warming cannot be solved in a day"，意为全球变暖问题不能在一天之内解决，并非完全无法解决，B选项表述错误。
5. 全文先介绍地球变暖的原理，核心内容围绕缓解、阻止全球变暖的方法展开，最后呼吁大家行动保护地球，最贴合的标题是"我们如何阻止地球持续变暖"，其余选项都只覆盖了文章的部分内容，不够全面。