A:for getting
B:of getting
C:to get
D:to getting
如图所示电路,电源电动势为E,串联的固定电阻为R2,滑动变阻器的总电阻为R1,电阻大小关系为R1=R2=r,则在滑动触头从a端移动到b端的过程中,下列描述中正确的是( )
It is difficult ____ (arrive) for class. It is raining.