初产妇上产床待产应在宫口开大()
A.3cm
B.4cm
C.6cm
D.8cm
E.10cm
参考答案:E
解析:初产妇一般在宫口开全(10cm)进入第二产程时上产床待产。
Mr. Green, for _____ life had been very hard, donated his possessions to earthquake-hit families in Sichuan.
A. whose B. whom B. which D. that
用得最多也是最重要的离中量数是( )
A.异众比率
B.四分位差
C.标准差
D.全距