Wang Lifei likes films. He often ______ VCDs. [ ]
A. watches
B. listens to
C. watch
答案:A
A.5A
B.5A
C.5/2A
D./2A
正常情况下,如将频谱多普勒舒张期取样容积位于二尖瓣上左房腔内可观察到()
A.负向双峰频谱
B.形态与二尖瓣口血流频谱相差较大
C.E/A比值常≤1
D.频谱幅度高于二尖瓣口血流
E.E/A比值常≥1