一个阻值为R的电阻两端加上电压U后,通过电阻横截面的电量q随时间t变化的图象如图所示,此图象的斜率可表示为( )
A:U
B:R
C:UR
D:1R
We used to see each other _____, but haven't heard from him since last year.
查字典,做题
“张”在字典中的解释有:A.使合拢的东西分开 B.看;望 C.量词