It is usually warm in my hometown in March, but it ______ be rather cold sometimes.
A:must
B:can
C:should
D:would
读我国局部图,回答问题。
某台电动机两端电压为6V时,通过的电流为1A,其阻值为0.5Ω的线圈在5min内产生的热量是____ J;我们把这种电流通过导体产生热量的现象称为电流的____