文章大意：这是一篇说明文。当涉及到脑震荡和其他形式的脑损伤时，像美式足球和冰球这样的运动得到了最多的关注。一项新的研究发现，经常头球的球员比那些不太可能用头的球员更容易遭受永久性脑损伤和记忆力受损。
10 . 根据提示用本部分所学词汇的正确形式完成下列短文（每空一词）
Sports like American football and ice hockey get most of the attention when it comes to concussions (脑震荡) and other forms of brain injury. But soccer is a(n) 1 (激烈的) sport for which the head can be as important as the foot.
Heading the ball is a key soccer skill. But a new study finds that players who head the ball frequently are more likely to suffer 2 (长久的) brain injury and damage their memory than players who are less likely to use their heads.
“For many people, it’s beyond belief that a slight injury could be a problem,” said Dr. Michael Lipton, an expert of neuroradiology (神经放射学) in New York City.
Lipton and his team interviewed 37 adult soccer players from New York City and took high-tech scans (扫描) to 3 (检查) their brains. They also asked the players how often they played soccer and how often they headed the ball, and they gave the players some neurocognitive tests.
The 4 (结果) was that the researchers found no link between small amounts of heading and players’ attention, ability to control their 5 (速度) when they move, or ability to manage complex thinking tasks. However, Lipton warned players not to ignore the possible risks of heading the ball too many times. Players could safely head the ball 885 to 1,550 times a year. It took almost 1,800 times a year for players to have trouble with their memory.
