已知长方体形的铜块长、宽、高分别是2cm、4cm、8cm，将它熔化后铸成一个正方体形的铜块，铸成的铜块的棱长为(不计损耗)( )。
A．4cm
B．6cm
C．8cm
D．10cm
参考答案：A
解析：
熔化前后铜块的体积不变，由V长方体=V正方体，可求得正方体的体积，从而求得其棱长。长方体中，长a=2cm，宽b=4cm，高c=8cm，则有V长方体=abc=2×4×8=64(cm3)。设正方体棱长为x，因为熔化前后铜块体积不变，因此：V正方体=x3=64，解得x=4，正确答案为A。
| 阅读理解。 |
| Jim was five years old. On his birthday he got a lot of birthday presents from his family,and one of them was a beautiful drum (鼓). It was from his grandpa. Jim liked his drum very much.He made a terrible noise with it, but his mother didn't mind. His father was working during the day, and Jim was in bed when he got home in the evening, so he didn't hear the noise. But one of the neighbors didn't like the noise, so one morning a few days later, she took a sharp knife and went to Jim's house while he was hitting his drum. She said, "Jimmy, do you know there's something nice inside your drum? Here's a knife. Open the drum and see what it is." |
| 1. Jim's gave him a drum on his birthday. |
[ ] |
| A. grandmother B. mother C. grandfather D.father |
| 2. liked the drum very much. |
[ ] |
| A. Jim B. Jim's father C. Jim's mother D. Jim's neighbor |
| 3. , Jim made a terrible noise with the drum. |
[ ] |
| A. Day and night B. Only during the day C. Only during the night D. When his dad was at home |
| 4. There was inside the drum. |
[ ] |
| A. something nice B. a nice knife C. nothing D. a lot of things |
| 5. The neighbor . |
[ ] |
| A. liked Jim very much B. gave him a sharp knife as his birthday present C. didn't want to hear the noise any more D. told him to stop hitting the drum |