涡轮流量计的旋转是流体作用于叶轮上的螺旋叶片（）形成的。
A、推力
B、拉力
C、摩擦力
D、弹性力
参考答案：A
The old couple decided to ______ a boy and a girl though they had three of their own.
A．adapt
B．bring
C．receive
D．adopt
