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 fast­paced world."可知，电子屏幕虽然有害，但是这个高速发展的科技社会需要大脑也做出一些改变来适应。

　　3．What does the underlined part "turn back the clock" in Paragraph 5 mean?

　　A．Stay away from screens.

B．Forget the good old days.