A.Because they are easier to control. |
B.Because they waste less material. |
C.Because they look exactly alike. |
D.Because they feel and bounce alike. |
A.when friction is greater |
B.when friction is less |
C.when it is heavier |
D.when it bounces strangely |
A.it is wet | B.it is dry |
C.there's a logo on it | D.its weight remains the same |
A.灰尘 | B.细菌 | C.汗水 | D.雨水 |
A.a synthetic ball takes in water faster than a leather ball |
B.a leather ball is more difficult to make than a synthetic one |
C.a synthetic ball is more expensive than a leather ball |
D.a leather ball may increase its weight during a game |