阅读理解

       Do you know there are two kinds of football games? One is American football, the other is soccer. In China many young men like playing soccer. It is very popular in China. But the Chinese don't call it soccer. They call it football. There are eleven players in a team. And the ball is round. Only the goal-keeper ( 守门员 ) can play the ball with hands. The other players must play the ball with feet.

       In America soccer is not very popular. I like playing American football more than playing soccer. There are also eleven players in a team. The ball is not round. All the players play the ball with hands and feet. American football is quite different from soccer.

根据短文内容完成句子

1. The Chinese call soccer            .

2. There are            players in a team of soccer and also in a team of American football.

3. In USA, people play football with hands and _____.

4. Only the             can play football hands in England.

5. American football is                from soccer.

请结合实际情况，说说用来制造手术刀的金属应具有什么样的性质？

_______________________________________________________