导致脐带脱垂的常见原因有()①盆头不称②先露入盆受阻③胎盘位置较低④脐带过长
A.①
B.①②
C.①②③
D.①②③④
E.④
参考答案:D
I'd appreciate ____ if you would like to teach me how to use the computer.
[ ]
A. that
B. it
C. this
D. you
能够被碱水解的是()。
A.蟾毒类
B.紫花洋地黄苷A
C.薯蓣皂苷
D.β—胡萝卜苷
E.胆酸