在图示电路中,在开关S闭合情况下试求A点的电位()。
A.VA=-5V
B.VA=5V
C.VA=-2V
D.VA=2V
参考答案:D
可发生反常呼吸运动的胸部疾病是()
A.多根多处肋骨骨折
B.闭合性气胸
C.张力性气胸
D.急性脓胸
E.慢性脓胸
You used to be short, _____? [ ]
A. weren't you
B. didn't you
C. don't you
D. used you