A client who is planning a pregnancy asks the nurse about ways to promote a healthy pregnancy. Which of the following would be the nurse’s best response

A. "Pregnancy is a human process; you don’t have to worry. "
B. "You practice good health habits; just follow them and you’ll be fine. "
C. "There is nothing you can do to have a healthy pregnaney; it’s all up to nature. "
D. "Folic acid, 400 mcg(1mcg= 10μg), improves pregnancy outcomes by preventing certain complications. "

（）的每个行星齿轮同时与两个半轴齿轮啮合，这就把十字轴传来的动力传给了半轴齿轮。

A.减速器

B.差速器

C.主减速器

D.轮边减速器