题目内容：

A study led by child psychologist Dr Richard Woolfson suggests that children aged between 7 and 14 experienced twice the cognitive processing speed(认知处理速度) and performed better in testing after watching 20 minutes of a 3D film.

This is despite suggestions that attention spans in children have shortened in the last decade due to unlimited to 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 shortening of response times after watching 3D was almost three times as big as that gained from watching 2D; in other words, 3D helps children process aspects of their environment more quickly. This is likely to be because 3D is a mentally stimulating experience which 'gets the brain's juices flowing'."

The experiment saw children given a range of cognitive tests before watching 20 minutes of a movie in either 2D or 3D and being tested again. The results showed those who saw the 3D content reacted faster and performed better in the second round of testing. Mental engagement also rose by 13% among 3D watchers.

Child psychologist Dr Woolfson added that "supportive parenting" and regularly listening to classical music can also aid a child's memory. "Children now expect to flit( 转换) from activity to activity in a matter of seconds, leaving them struggling when they need to concentrate for longer, for instance, during a classroom learning experience." he said.

1.According to Mr. Fagan, why can 3D movies help to make children smarter’ ?

A. Their content is better than that of 2D

B. They have a similar effect to brain-training exercise.

C. They can help children react faster and perform better.

D. They can process aspects of the environment quickly.

2.Which of the following is NOT true?

A. All children performed better after watching a 3D film

B. The children experimented on were tested at least twice.

C. Dr Woolfson said children now have trouble concentrating for long.

D. Unlimited access to entertainment has shortened attention spans in children.

3.What is the main idea of the passage?

A. How watching 3D movies exercises the brain.

B. Watching 3D movies is not good for attention spans in children

C. A study suggests that 3D movies can help to make children smarter.

D. A study claimed that compared with 2D, watching 3D content is better.