问题
选择题
Jim doesn’t like the soap operas at all. He can't ____ them. [ ]
A. love
B. stand
C. understand
D. know
答案
答案：B
搜题请搜索小程序“爱下问搜题”
Jim doesn’t like the soap operas at all. He can't ____ them. [ ]
A. love
B. stand
C. understand
D. know
答案：B
请用已经量的符号表示下列机械的有用功和总功
| 机械 | 已知条件 | 有用功W有 | 总功W总 |
| 抽水机 | 电源电压U、通过电动的电流I、通过时间t、抽水高度h、抽水的质量m | ||
 | 如左图： 用力F将重G的物体匀速移动s，物体受到的摩力是f |