C．Behave younger and healthier.

　　D．Change the time shown on the clock.

　　解析：选A　词义猜测题。由画线部分之后的"...think of the good old days when you were a kid ...'I didn't do that and I didn't have TV and look how great I turned out'"可知，turn back the clock意指回到过去没有电子屏幕的生活。

　　4．What does Gina suggest parents do in the last paragraph?

　　A．Learn more from each other.

　　B．Don't limit screen time for their kids.

　　C．Be cautious about screen time for their kids.

　　D．Encourage their kids to learn more from screens.

　　解析：选C　推理判断题。由最后一段Gina说的话可知，相同的面对屏幕的时间对于不同的孩子来说影响也不同，所以父母们不能轻率地做出决定。

　　Ⅱ.语法填空

　　Millions of Americans are mourning (哀悼) the death of astronaut John Glenn, who passed away __1__ (peaceful) on December 8, 2016 at the age of 95.President Donald Trump said, "The US has lost a great pioneer in space travel."

　　Glenn __2__ (start) his flying career as a fighter pilot. In 1959, Glenn became one of seven test pilots __3__ (choose) to take part in the first space program of the US.

　　Glenn rose to fame in 1962 when he became the first American __4__ (circle) the Earth in a spaceship. The journey made him __5__ American hero. As a member of the Democratic Party, Glenn first won the election to the Senate (参议院) in 1974 and served for 24 years __6__ January 3, 1999.

　　Glenn was known for his modesty, refusing to see __7__ (he) as a hero. He preferred to focus on his work, saying, "The greatest people are those __8__ devote themselves to something __9__ (important) than merely their own self­interest."

　　On October 29, 1998, when Glenn was 77, he returned to space and stayed there for nine days, thus __10__ (set) the record for being the oldest person in space.

语篇解读：本文是说明文。2016年12月8日，美国首位绕地球飞行的宇