Twenty years ago, when Andrew Westbrook was in college, he had a hard time focusing in class. When it came to some mental tasks, thinking was difficult and his attention wandered（开小差）.
Westbrook is now a scientist. His research is challenging old ideas about why we can't keep our attention on certain tasks.
For years, scientists thought difficult mental tasks needed more energy than easy ones.
However, Westbrook's research suggests our brain is always working hard. Even when we are looking around, our brain is dealing with much information and using lots of energy. The real problem is that difficult tasks need different brain areas to work together in new ways, which makes people feel uncomfortable.
“Thinking about beginning a hard task feels harder than actually doing it,” Westbrook says. This early mental difficulty can make us put off the task. “If we can get over it, thinking will become easier,” he adds.
Westbrook's team has found ways to help us focus better. We can pay attention to the good results of finishing the task. We can also get into “flow” by setting a clear goal. Finally, we can turn difficult tasks into a daily habit.
()46. How does the writer lead in the topic?
A. By giving an example.
B. By showing advice.
C. By asking questions.
D. By listing numbers.
()47. What did scientists use to believe?
A. Easy tasks use more energy.
B. Hard tasks need more energy.
C. The brain works hard all the time.
D. Looking around needs no energy.
()48. What does the underlined word “it” in Paragraph 5 refer to?
A. An old idea.
B. The mental difficulty.
C. The hard task.
D. A good beginning.
()49. What is the purpose of the text?
A. To explain why we lose focus and how to get better.
B. To show how difficult the mental tasks usually are.
C. To tell people the importance of developing good habits.
D. To introduce a great scientist called Andrew Westbrook.

46. A 47. B 48. B 49. A

【分析】
46题需判断作者引入话题的方式，文章开头讲述Andrew Westbrook大学时注意力不集中的经历，属于举例；47题定位原文关于科学家旧观点的表述，直接查找对应内容；48题代词指代需结合it前后语境，前句提到“early mental difficulty”，据此判断指代对象；49题需梳理全文内容，明确文章核心目的。
【解析】
46题：文章开篇以Andrew Westbrook大学时难以集中注意力的实例引入话题，属于举例说明，故选A。
47题：根据原文“For years, scientists thought difficult mental tasks needed more energy than easy ones.”可知，科学家过去认为难的脑力任务需要更多能量，故选B。
48题：代词指代题，it所在句前一句提到“This early mental difficulty can make us put off the task.”，结合语境，get over（克服）的对象是前文的“mental difficulty”，故选B。
49题：文章先介绍注意力不集中的原因（旧观点及新研究结论），最后给出帮助集中注意力的方法，核心目的是解释注意力不集中的原因并给出改善方法，故选A。
【答案】
46.A 47.B 48.B 49.A
【知识点】
英语阅读理解、细节理解题、代词指代题
【点评】
本题为英语阅读理解常规题型，考查细节查找、代词指代及主旨理解，需学生精准定位原文信息，结合语境分析，整体难度适中。
【难度系数】
0.5