【简答题】Rivers are one of our most important natural resources. Many of the world’s great cities are located on rivers, and almost __1_______ country has at least one river __2_______(flow) through it that pl...
【单选题】What’s the old days like according to the fish from the fable Forget Each Other in the Rivers and Lakes?
A.
They have a lot of friends supporting one another on the dried land
B.
There is so much water in the rivers and lakes that they forget the existence of other fish
C.
They have to live on each other’s saliva in the dried rivers and lakes
D.
They swim freely in big schools in the rivers and lakes
【多选题】一个电容为C的平行板电容器与电源相连,开关闭合后,电容器极板间的电压为U ,极板上的电荷量为q,在不断开电源的条件下,把两极板间的距离拉大一倍,则( )
【单选题】Which of the following is one of the world's greatest continental rivers?
【单选题】But much of the world’s water ____ from rivers and lakes.
【单选题】一个电容为 C 的平行板电容器与电源相连,开关闭合后,电容器的极板间的电压为 U ,极板上的电荷量为 q 。 在不断开电源的条件下,把两极板间的距离拉大一倍,则( )。
【单选题】With the country’s population increasing to 1.3 billion, many of China’s rivers, including the legendary Yellow River, .
【单选题】一个电容为 C 的平行板电容器与电源相连,开关闭合后,电容器板间的电压为 U ,极板上的电荷量为 q 。在不断开电源的条件下,把两极板间的距离拉大一倍,则( )。
B.
. U 不变, C 减小一半, q 增大一倍
【简答题】反对称阵Aii=()(i=1,···n)
【单选题】一个电容为C的平行板电容器与电源相连,开关闭合后,电容器板间的电压为U,极板上的电荷量为q。在不断开电源的条件下,把两极板间的距离拉大一倍,则( )。
A.
U不变,q和C都减小一半 B.U不变, C减小一半,q增大一倍
B.
q不变, C减小一半,U增大一倍 D.q、U都不变,C减小一半