It's uncertain ________ the experiment is worth doing.
A.if
B.that
C.whether
D.how
答案:C
--- I didn’t tell my parents the secret yesterday.
--- But you ______.
A.ought to do
B.ought to
C.should
D.ought to have
关于子宫收缩力,下列叙述哪项正确
A.是临产后的主要产力
B.具有节律性、对称性、极性、缩复作用
C.是第二产程娩出胎儿的重要辅助力量
D.具有协助胎先露在骨盆内旋转的作用
E.以上均不对