哪项易发生脐带脱垂()
A.脐带过长
B.部分性前置胎盘
C.足先露,胎膜早破
D.双胎
E.枕后位
参考答案:C
English is a language that many people around the world _______not speak perfectly but _________at least understand.
A.may,can
B.would,might
C.can,must
D.should,can
嵌体制作时,下列有关洞斜面的说法,正确的是()
嵌体制作时,下列有关洞斜面的说法,正确的是
A.洞斜面的角度为30°
B.斜面起于釉牙本质界层
C.预备斜面可去除洞缘无基釉,防止釉质折断
D.可增加嵌体的洞缘密合性
E.宽度为1.5mm