齿轮的传动比只与基圆半径有关，与两齿轮的中心矩无关。
参考答案：对
菟丝子与沙苑子的共同作用是（）。
A.温脾
B.止泻
C.润肠
D.明目
E.安胎
This is Susan and that is Mary. _ my _ .
A．She's, friend
B．He's, friend
C．They're; friends
D．They're, friend
