五、阅读理解。
One of the best parts of autumn is its beautiful colors. Normally green leaves turn into red, orange, yellow, and finally brown. This is called “leaf phenology”, and many people look forward to it every year. However, due to climate change, autumn is changing.
According to a study published（出版） earlier this year, the season length is growing, meaning that it is taking longer for leaves to change their colors. And this is not the only way that climate change is ruining（破坏） the season.
“Trees are holding onto their leaves longer,” explained Dr. Howard Diamond, a senior climate scientist. “When I was a kid, I can remember the leaves would drop a lot sooner 20 years ago than they do now. Research shows what we are seeing is real.”
Climate change isn’t just causing the leaves to change later. We can also expect later frosts（霜） according to Dr. Michael E. Mann, a professor at the University of Pennsylvania. Mann said, “That means mosquitoes（蚊子） and pests remain active for a longer time in autumn, posing（造成） a greater health risk to human beings.”
If there is any good news at all, though, we may be able to stave off this development. Mann pointed out that if humans limit their carbon dioxide emissions（二氧化碳排放）, they can still prevent the worst effects of climate change from affecting them during the autumn months. “A new study recently provides further evidence（证据） that surface warming will likely stop after carbon emissions reach zero,” Mann explained in his recent comment for *Live Science*.
()1. Which of the following is one of the effects（影响） of climate change on autumn?
A. The season length is becoming shorter.
B. Leaves are changing their colors earlier.
C. Leaves are staying on the trees for a longer time.
D. There are more frosts in autumn.
()2. What can we infer from Dr. Michael E. Mann’s words in Paragraph 4?
A. Mosquitoes will disappear completely if there are earlier frosts.
B. Later frosts in autumn are good for people’s health.
C. People should take measures to kill mosquitoes and pests in autumn.
D. The longer mosquitoes are active, the more dangerous it is for people.
()3. What does the underlined phrase “stave off” probably mean in Paragraph 5?
A. Make something happen faster.
B. Stop something from happening.
C. Change something completely.
D. Let something develop naturally.
()4. What is the author’s purpose in writing this passage?
A. To tell readers about the beautiful colors of autumn.
B. To introduce the research of Dr. Howard Diamond and Dr. Michael E. Mann.
C. To show how climate change is affecting autumn.
D. To draw people’s attention to environmental protection.
()5. Which of the following is the best structure of the passage? (①: Paragraph 1,…)

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

1. 细节理解题。根据第二段“the season length is growing”可知A错误；根据“it is taking longer for leaves to change their colors”可知B错误；根据第三段“Trees are holding onto their leaves longer”可知C正确；根据第四段“later frosts”可知D错误，故选C。
2. 推理判断题。根据第四段Dr. Mann的话“mosquitoes and pests remain active for a longer time in autumn, posing a greater health risk to human beings”可知，蚊子活跃越久，对人类健康越危险，D正确；A“完全消失”未提及，B“晚霜有益健康”与原文相反，C“应采取措施杀蚊子”未提及，故选D。
3. 词义猜测题。根据第五段“if humans limit their carbon dioxide emissions, they can still prevent the worst effects of climate change”可知，stave off意为“阻止”，对应B选项，故选B。
4. 主旨大意题。全文围绕气候变化对秋天的影响展开，作者目的是展示气候变化如何影响秋天，C正确；A是引入内容，B是细节，D不是主要目的，故选C。
5. 文章结构题。①段总起气候变化改变秋天；②段讲季节长度变化；③段讲叶子留存更久；④段讲晚霜及害虫影响；⑤段讲应对方法，对应选项C的结构，故选C。