尽可能用润滑条件良好的闭式齿轮传动结构代替开式齿轮传动结构，可以有效避免齿面磨损。
参考答案：对
_______ to change her schedule because the plane arrived late, the famous actress cancelled the appointment with the local press．
A．Forcing
B．Forced
C．To force
D．Being forced
如何理解餐饮服务的差异性？
