题干
—Did you call Sara back?
—I didn’t need to, _____ we’ll have a meeting together tonight.
—I didn’t need to, _____ we’ll have a meeting together tonight.
A：though
B：unle
C：because
D：if
答案(点此获取答案解析）
C
是理想电压表．现将负载电阻的阻值减小为R=5R0，保持变压器输入电流不变，此时电压表的读数为5.0V，则（ ）
