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问题 单项选择题

根据《SDH长途光缆传输系统工程验收规范》，SDH网络接口和数字段输出口的抖动性能得测试时间为（）。

A.180s

B.120s

C.60s

D.300s

答案

参考答案：C

阅读理解

Smartphone ,poor sight

Look around and you’ll see people busy on their smartphones. Smartphones do make our lives easier . But have you ever thought about what they mean to you eyes?

According to a study ,half of British people own smartphones and they spend an average of two hours a day using them . There has been a 35% increase in the number of people in the UK who suffer from shortsightedness since smartphones were introduced there in 1997.

Staring at smartphones for long time gives you dry eyes. When looking at something in the distance ,your eyes automatically blink a certain number of times. However ,when you look at things closer  to your face ,the blinking slows down . This reduces the amount of tears and causes discomfort in your eyes. Another bad habit is using  smartphones in dark rooms before going to sleep . If you look at a bright screen while your pupils become larger ,too much light enters your eyes. This can do harm to the eyes and cause a disease called glaucoma.

While you’re probably not going to stop using to your smartphone,there are a few things you can do to protect your eyes. Hold  your phone at least 30 continues away from your eyes when using it. Take a break every hour and try the following :look at something at least five meters from you and then focus on the tip of your nose. Repeat this several times. It should reduce the discomfort in your eyes.
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结婚自由是指婚姻当事人有权按法律规定自己决定自己的婚姻，父母和任何人不得干涉。
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