因为23x=12y,
则x:y=12:23=3:4;
故选:B.
—Has she got a dog?
—_____. It is black and white. [ ]
A. Yes, she is
B. Yes, she has
C. No, he has
D. No, she isn't
右心衰竭引起呼吸困难的原因为()
A.右心房压力升高刺激化学感受器而兴奋呼吸中枢
B.代谢产物减少刺激呼吸中枢
C.淤血性肝肿大等使运动受限而减少肺交换面积
D.腹腔积液通过膈肌兴奋呼吸中枢
E.胸腔积液通过膈肌兴奋呼吸中枢