估计胎儿生长发育,与下列哪项无关
A.宫高
B.胎儿股骨长度
C.胎儿胸围
D.胎儿双顶径
E.胎儿腹围
参考答案:C
Some children are too selfish today. They should be taught to _____things with others so that they will
show concern for others. [ ]
A. live
B. give
C. share
D. enjoy
液压驱动元件的作用是将()输入的机械能转变成液体的压力能,为液压系统提供动力。