队员移动中接球一脚着地，可以跳起这只脚，再双脚同时落地，此时（）是中枢脚。
参考答案：双脚
At least ten people were injured in the accident,two girls .
A．contained
B．included
C．including
D．were included
有一批汽车用板弹簧，材料为60Si2MnA，试问应选择的热处理工艺（）
A.正火
B.调质
C.淬火+中温回火
D.退火
