动压润滑轴承是利用外界的油压系统供给一定的压力润滑油，使轴颈和轴承处于完全液体摩擦状态。
参考答案：错
You can hardly imagine the difficulty the woman had _____ her children.
A．brought up
B．to bring up
C．bringing up
D．to have brought up
