有一导体，加在其两端的电压是2V时，通过的电流是1A，导体的电阻是2Ω，如果加在导体两端的电压改为4V，导体的电阻为_______Ω．
2
下列哪种补体低下可作为SLE活动的指标之一（）
A.C3
B.C2
C.C4
D.C6
E.CH50
_______ you keep on practicing English, I’m sure you will be able to speak it fluently.
A．As soon as
B．As long as
C．Even if
D．As if
