题目内容：

    We humans love to stare into our smart devices.We gaze for hours—about 10 hours and 39 minutes a day—at our computers，smartphones，tablets and televisions.Is all this staring bad for us? It might be，mainly because as we stare at our devices we are exposing ourselves to blue light.

Blue light is a type of electromagnetic radiation with a very short wavelength that produces a high amount of energy.While it's true that light can damage our eyes under certain circumstances，there's no scientific evidence suggesting that blue light is harmful to our eyes.But many people still think it is，which is why blue light—blocking glasses are so popular.So do the glasses work?

“Everyone is very concerned that blue light may be causing damage to the eye，but there's no evidence that it may be causing serious damage，”Dr.Rahul Khurana，clinical spokesman for the American Academy of Ophthalmologists，told Business Insider.

Blue light exposure is nothing new.In fact，the sun is the largest source of blue light.Moreover，blue light is also present in LED light.But if blue light isn't harmful，then why are we constantly rubbing our eyes when we’re looking at our screens? The answer is eyestrain(眼疲劳):More than 60 percent of people experience eye problems associated with digital eyestrain.And blue light，it seems，isn't the cause.Instead，our eyes are so strained because most of us blink less when we stare at our digital devices.So if eyestrain is the real issue，blue light-blocking glasses are probably of little use.

1.What do we know about blue light?

A. It is a kind of nuclear radiation.

B. It has the shortest wavelength.

C. It may come from electronic devices.

D. It consumes a great deal of energy.

2.What causes the popularity of blue light-blocking glasses?

A. Evidence of their benefits to eyes.

B. Belief in blue light's harmful effect.

C. Widespread use of smart devices.

D. Scientific understanding of blue light.

3.What can be inferred from Paragraph 4?

A. Blue light exposure is hardly avoidable.

B. Eye problems are not easy to deal with.

C. Blue 1ight may connect with tired eyes.

D. Rubbing eyes makes people strained.

4.According to the text，wearing blue light-blocking glasses may be_______.

A. tiring B. harmful C. useless D. beneficial