In fall 2006, the National Basketball Association(NBA)started using basketballs made with synthetic, or man-made, material inste

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问题     In fall 2006, the National Basketball Association(NBA)started using basketballs made with synthetic, or man-made, material instead of leather. They made the change because they wanted every basketball they use to feel and bounce the same. Not all leather balls are exactly alike in weight or how they bounce, but the synthetic balls are.
    However, some players complained right away that the new balls bounced differently and were actually harder to control than the leather ones.
    Physics helped answer questions about why the new balls felt different. For example, the scientists studied friction, which in this case affects the ability of a player to hold onto a ball. " The greater the friction, the better it will stick to his hand," explains a scientist.
    Tests on both wet and dry balls showed that while the synthetic ball was easier to hold onto when dry, it had less friction and became much harder to hold onto when wet. That’s because sweat stays on the surface of the synthetic balls but gets taken into the leather balls.
    The scientists also tested bounce and found that the logo printed on the new balls made their surface uneven and caused them to bounce a little strangely compared with the leather balls.
    In January, the NBA went back to using the leather balls. They aren’t perfect, but for now, that’s just the way the ball bounces.
The underlined word "They" in the last paragraph refers to______.

选项 A、the synthetic balls
B、the leather balls
C、the ball players
D、the scientists

答案B

解析 推断判断题。本题考查指示代词,They的指代对象应从距其最近的上句寻找,分析they的上句可知,They指代Leather balls。全句意思是:一月份起,NBA重新使用皮革材料制成的球,虽然这种球并不完美,但就现在来说,它们达到了弹跳的最佳方式。
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