导致胎儿缺氧的母体因素有:
A.微小动脉供血不足
B.红细胞携氧量不足
C.急性失血
D.各种原因引起的休克与急性感染发热
E.子宫胎盘血运受阻
参考答案:A,B,C,D,E
--- May I use your mobile phone?
--- _________ .
A.Why not?
B.Go ahead.
C.OK, enjoy yourself
D.Yes, but you’d better not.
将洋葱表皮细胞放在30%的蔗糖溶液中,细胞发生了质壁分离,则此细胞的原生质与细胞壁之间的物质应是()
A.水
B.低于30%蔗糖溶液
C.等于30%的蔗糖溶液
D.高于30%的蔗糖溶液