横剌又称平刺,是指针身与皮肤呈:()
A.15°
B.25°
C.35°
D.45°
E.90°
参考答案:A
30. My parents have promised to come to see me before I _____ for Africa.
A.have left
B.leave
C.left
D.will leave
中链三酰甘油的脂肪酸碳原子数为()。
A.6~8
B.6~12
C.12~16
D.18~22
E.23~26