题目内容：

Watching a 3D movie can more than double the concentration powers and the cognitive（认知的）process of children,new re-search claims.

A study by visual technology firm Read and led by child psychologist Dr Richard Woolfson and associate lecturer at Goldsmiths Patrick Fagan suggests that children aged between 7 and 14 experienced twice the cognitive processing speed and performed better in tests after watching 20 minutes of a 3D film.

This suggests that children's attention spans have shortened in the last decade due to unlimited access to entertainment,including on-demand TV,gaming and social media.

A 2015 study claimed that watching 3D content had a similar effect to brain-training exercises.

Consumer psychologist Mr Fagan said that the increased stimulation found in watching something in 3D "exercised" the brain and improved performance in the short term.

3D films can play the role of brain-training "games and help to make children 'smarter' in the short term," he said. "The response speed after watching 3D was almost three times as quick as that gained from watching 2D; in other words,3D helps children process aspects of their environment more quickly.This is likely because 3D is a mentally exciting experience which 'gets the brain's juices flowing'."

1.How do we know the benefits of watching a 3D film?

A. Through introduction.    B. By taking an exam.

C. Through research.    D. By watching TV shows.

2.What's the meaning of the underlined word "stimulation" ?

A. Excitement.    B. Contents.

C. Cost.    D. Time.

3.Why does 3D have an advantage over 2D?

A. The time of watching 3D is short.

B. 3D can increase the reaction speed.

C. 3D can make children adapt the surroundings more quickly.

D. 3D can make more brain's power

4.What may be the best title for the text?

A. How 3D forms    B. What are 3D films

C. A study on 3D films    D. 3D films benefit children