产前出血中，流出的是胎儿血的是（）
A.前置胎盘
B.胎盘早剥
C.宫颈息肉
D.前置血管破裂
E.边缘血窦破裂
参考答案：D
―She didn’t come to school yesterday, ?
― , though she was not feeling well.[ ]
A. did she; Yes, she did
B. did she; No, she didn’t
C. didn’t she; Yes, she did
D. didn’t she; No, she didn’t
硬质合金钻头切削具的切削角A＞90º时，叫（）镶。
A.直
B.正前角斜
C.负前角斜
