Do you have a smartphone? It’s very useful—we can use it to take photos, play games or study. But it can also cause（造成）problems. A large number of people spend more than 4 hours a day using their phones — that’s 1,460 hours a year, from a study by Thames. If we use smartphones too much, they can become harmful（有害的）.

Using smartphones too much can be bad for students’ study. What about sleep? Many studies show that long smartphone time is bad for students’ sleep, too. It can make it hard to fall asleep and even harder to wake up in the morning.

To find out if using smartphones too much causes poor sleep, scientists asked 1,043 British students aged between 18 and 30 to finish two questionnaires（问卷）. And they find that using smartphones too much brings people poor sleep. Almost 70% of the students who use smartphones too much have poor sleep.

If you have a smartphone, it’s a good idea to put down your phone before you go to sleep. Try spending less time on smartphones, and see what happens.

Wang Xiaojun is twelve years old. He lives in the countryside in Hubei. Today is April twenty fourth. It’s his birthday. His parents make a nice dinner for him, but the boy says, “I will not have dinner because after dinner,   today is over, and my parents are going to Shenzhen tomorrow.   I don’t want to let them go”.

His parents went to Shenzhen to work three years ago. They only come back this time for their son’s 12^th birthday. Tomorrow they have to go back to Shenzhen.

Wang is not the only stay-at-home child(留守儿童). In China there are many children staying at home without their parents. Stay-at-home children have a lot of problems. Most of them stay with their grandparents. Some of them don’t study well because their parents cannot help them with their study.

The Chinese government(政府) now is trying to solve their problems.