法洛四联症患儿喜蹲踞是因为这能使
A.心脑供血量增加
B.缓解漏斗部痉挛
C.腔静脉回心血量增加
D.休息,缓解疲劳
E.体循环阻力减少,减少右向左分流血量
参考答案:E
Sunday is my birthday. I would like _____ a birthday party, would you _____ to my party? [ ]
A. have; come
B. to have; to come
C. have; to come
D. to have; come
钻井绞车用作起升的核心部件是()。
A.传动轴
B.变速轴
C.滚筒轴
D.中间轴