A number of scientific studies have suggested that repeatedly heading a football could increase the risk of developing dementia (痴呆症) in later life.
In 2002, former England international footballer Jeff Astle died aged 59. A coroner (验尸官) said that Astle died from a brain disease likely to have been caused by “repeated small damages to the brain” related to heading a heavy leather football.
Dr. Scott Delaney, research director of emergency medicine at McGill University Health Center in Montreal, Canada, has also researched soccer-related head injury and agrees that head-to-head or elbow-to-head blows are the real risk.
In 2007, Delaney carried out a study on footballers aged between 12 and 17 that showed they were half as likely to be concussed (使脑部受到震荡) wearing headgear (帽) than without.
He said youngsters have a higher risk of head injury than adults because their heads are thinner and less able to absorb shock. To make matters worse, their neck muscles aren’t as well developed and they often lack the correct heading technique that can help throw away the force of the ball.
Delaney recommends that children wear headgear when playing football and says his two eldest children wear head protection playing the sport. But he admits that children can be unwilling to be the first to wear head protection—especially when their football heroes play without it.
While headgear can protect footballers from being concussed during a match, no one knows the long-term effects of repeated “sub-concussive” blows to the head.
Delaney says that while there is indirect evidence that a career in soccer can lead to dementia, no one has yet found a sure link between the two. He says proving a link would mean monitoring hundreds of footballers for three or four decades—and that would take a lot of funding.
Which might be the best title of the passage?

A．Playing football may lead to brain damage.

B．Repeated small damages to the brain.

C．Footballers should wear headgear when playing. .

D．Evidence to dementia.

According to Delaney’s research, what is the most risky injuries to head?

A．Long-term effects of blows.

B．Wearing head protection.

C．Underdeveloped neck muscles.

D．Head-to-head or elbow-to-head blows.

Children are unwilling to wear headgear because they think _____ .

A．headgear is harmful to their heads	B．headgear influences their skills
C．they should follow their idols	D．they mustn’t lead the fashion

It can be inferred from the last paragraph that _____ .

A．Delaney has studied dementia for three or four decades

B．few footballers would like to be studied in the research

C．funding is important in order to carry out the research.

D．no one can find the link between playing football and dementia