A.1.6~1.8cm,3.0cm B.2.6~2.8cm,4.0cm C.3.6~3.8cm,5.0cm D.4.6~4.8cm,6.0cm
A.胎盤老化 B.易發(fā)生胎兒窘迫 C.羊水量增多 D.胎兒皮下脂肪變薄
A.①② B.②④ C.①④ D.②③