当流过用电器的电流一定时,电功率与电阻值成(),当加在用电器两端的电压一定时,电功率与电阻成()。
参考答案:正比 反比
When your parents haven’t ____your letter for a long time,they will worry about you.
A.heard
B.heard from
C.received
D.accepted
若二维数组b有m列,则在b[i][j]前的元素的个数为 【7】 。