在北半球船舶从锋面气旋的低纬一侧通过,观测到气压变化趋势为()。
A.先降、后升、再平
B.先升、后降、再升
C.先平、后降、再升
D.先降、后平、再升
参考答案:D
A.电源电动势是表示电源本身特性的物理量,它不随外电路的电阻变化而变化
B.在一个闭合电路中,路端电压不可能大于电源电动势
C.在闭合电路中,路端电压随外电路的电阻增大而增大
D.在闭合电路中,路端电压随外电路的电阻增大而减小
—What do you think of the book about Harry Potter ?
—I like it very much. It's _ interesting ______ exciting. [ ]
A. neither, nor
B. not, but
C. not only, but also
D. either, or