The debate centered on a study of young mice exposed to a video game."The mice showed big changes everywhere in the brain，" said researcher Ramirez.On the positive side, it meant that these mice were able to stay calm in an environment that would have stressed out a normal mouse.But it also meant they acted like they had a lack of attention, showed signs of learning problems, and were likely to do dangerous behavior.Generally, the results add to the evidence that parents should be very cautious about screen time for young children, Ramirez said.

　　A more positive explanation came from Professor Leah Krubitzer."The benefits may be more important than the negative sides，" Krubitzer said, adding that a less sensitive brain might succeed in a world where overstimulation (过度刺激) is a common problem.

　　It's true that this sort of stimulation may make a child's brain less sensitive in some ways.But it also may prepare the brain for an increasingly fast­paced world."Less than 300 years ago we had an industrial revolution and today we're using mobile phones and we interact (互动) on a regular basis with machines，" Krubitzer said."So the brain must have changed."

　　Krubitzer rejected the idea that the best solution is to turn_back_the_clock."You are likely to think of the good old days when you were a kid, and say, 'I didn't do that and I didn't have TV and look how great I turned out，'" Krubitzer said.

　　Brain researcher Gina Turrigiano thinks lots of screen time may be fine for some young brains, but a problem for others."Parents have to really realize the fact that each kid is going to respond very differently to the same kinds of environments，" she said.

　　语篇解读：本文是议论文。电子屏幕对孩子的大脑发育有损害，但同时也被这个高速发展的科技社会所需要。

　　1．What damage did the screen time cause to the mice?

　　A．They have difficulty in focusing.

　　B．They are no longer afraid of danger.

　　C．They change their nature completely.

　　D．They get used to a stressful environment.

　　解析：选A　细节理解题。由第二段" ...they acted like they had a lack of attention, showed signs of learning problems, and were likely to do dangerous behavior."可知，这些老鼠的注意力下降，出现了学习障碍，以及有危险行为倾向。

　　2．Why do kids today need screen time according to Krubitzer?

　　A．They are too sensitive to changes.

　　B．They learn how to succeed from it.

　　C．It is needed in social development.

　　D．It protects them from overstimulation.

解析：选C　细节理解题。由第四段"But it also may prepare the brain for an increasingly