According to a 2018 study from San Francisco State University, nearly 2.4 billion people around the world used a smartphone in 2017. By the end of 2019, more than a third of the global population will be using a smartphone.
   However, smartphone technology can be a double-edged sword. On the one hand, it sends us unlimited amounts of information. On the other hand, using a smartphone may become an addiction.
   Erik Peter and Richard Harvey are both health education professors at San Francisco State University. They led the study. Peter explains that smartphone addiction forms connections in the brain that are similar to drug addiction. And these connections form slowly over time. Also. addiction to social media may affect our emotional state. The two professors asked 135 university students about their habit of smart6phone use and their feelings. They found that students who used their phones the most reported higher levels of feeling lonely, depressed and anxious.
    Peter and Harvey do not blame users for their technology addiction. They believe it is the teach industry’s desire to make more money that is to blame for the technology addiction. The researchers warn that workers in the technology industry know how to control our brains and turn us into addicts.  
   But the researchers say that we can train our brains to be less addicted to our phones and computers. Erik Peter suggesting turning off our phones before we sleep or do something important. The researchers also suggest taking control of when and where you answer texts or emails. You do not need to answer them all. And you certainly don’t need to answer them as soon as you get them. They also suggest putting limits on the time you spend on social media. If you want to catch up with friends on Facebook, set aside a small amount of time to it. You should focus on important tasks and do not allow technology to disturb you.
根据短文内容选择最佳答案。
46. What can we infer from Paragraph1?
A. Smartphone use has become extremely common.
B. Most young people can’t live without smartphones.
C. Smartphones make our life more colorful and convenient.
D. Most people consider smartphones as the greatest invention.
47. The underlined sentence in Paragraph 2 means smartphone technology _________.
A. has a brilliant future    B. can be better than most people think
C. has both advantages and disadvantages   D. can give us unlimited amounts of information
48. What did Erik Peter and Richard Harvey find about smartphone use?
A. It can help reduce loneliness.   B. It’s more popular with students.
C. It’s preferred by young people feeling lonely.
D. It can harm students’ emotional state in many ways.
49. What does the last paragraph mainly want to tell us?
A. Social media isn’t that important to us.
B. We can train our brains to do many things.
C. We shouldn’t become addicted to our smartphones.
D. There are ways to deal with smartphone use addiction.
50. Which of the following is True?
A. We can use smartphones to deal with loneliness.
B. An addiction can’t be controlled if we still use smartphones.
C. There were nearly 2.4 billion people using smartphones in the world in 2017.
D. Stop using smartphones if you don’t know when and where you should answer the emails.

题材：说明文

话题22：科普知识

词数：324

【答案】46~50 ACDDC
【解析】
【主旨大意】本文是则科学调查，属于说明文范畴。研究表明：全球将有过三分之一的人口在使用智能手机。而智能手机是把双刃剑，一方面它能发送无限量的信息，另一方面它会损害人的健康。例如使用手机最多的学生会感到孤独、沮丧或焦虑程度更高等，所以，研究人员建议控制手机使用时间，要合理使用手机。
46.A推理判断题 根据第一段大意：2017年有24亿人使用智能手机，到2019年底，将有超过三分之一的人口使用手机，说明智能手机越来越普遍，故选A。
47.C细节理解题 根据句意“智能手机是把双刃剑”可推知：使用智能手机有好处也有坏处，故选C。
48.D细节理解题 根据两位教授的调查可知：智能手机成瘾在大脑中形成毒瘾，对学生造成严重危害，故选D。
49.D段落大意题 根据研究人员提出的建议：可以训练大脑减少对手机和电脑的依赖，可知：我们有多种办法来对付手机成瘾，故选D。
50.C细节理解题 根据第一段中的nearly 2.4 billion people around the world used a smartphone in 2017.可知C项是正确的。