在电路中两点之间的电位差叫做()。
参考答案:电压
—What do you think of the two pairs of shoes?
—They don't fit me well. They are ______ too big ______ too small. [ ]
A. either; or
B. not only; but
C. both; and
D. neither; nor
明代万里长城的东西部起点在哪里?入海石城是谁下命修建的?