阅读短文，从下面每题的A、B、C、D四个选项中选出最佳选项。

According to a 2018 study from San Francisco State University, nearly 2. 4 billon people around the world used a smartphone in 2017. By the end of 2018, more than a third of the global population will be using a smartphone.

However, smartphone technology can be a double-edged sword (双刃剑). On the one hand, it sends us lots of information. On the other hand, using a smartphone may become an addiction (瘾).

Erik Peper and Richard Harvey are both health education professors at San Francisco State University. They led the study. Peper explains that smartphone addiction forms connections in the brain that are similar to drug addiction (毒瘾). And these connections form slowly over time. Also, addiction to social media may affect (影响) our emotional state (情绪). The two professors asked 135 university students about their habit of smartphone use and their feelings. They found that students who used their phones were feeling lonelier and more nervous.

Peper and Harvey don't blame (责怪) users for their 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 Peper suggests 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 don't need to answer them all. And you certainly don't need to answer them as soon as you get them. They also suggest setting limits (设限) on the time you spend.

【小题1】What can we infer from Paragraph ?

A．Smartphone use has become very common.

B．Most young people can't live without smartphones.

C．Smartphones make our life more colorful and convenient.

D．Most people think smartphones are the greatest invention.

【小题2】The underlined sentence in Paragraph 2 means smartphone technology ________.

A．has a bright future	B．can be better than most people think
C．has both advantages and disadvantages	D．can give us lots of information

【小题3】What did Erik Peper and Richard Harvey find about smartphone use?

A．It can beat 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.

【小题4】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.