推力滚动轴承的调整方法：（）
A、是在箱体上加衬垫调整轴向间隙
B、是用箱体上的螺纹调整轴向间隙
C、在箱体上加套
参考答案：A, B
So serious that all the persons on board were killed.
A．was the accident
B．did the accident
C．the accident was
D．the accident did
心绞痛与急性心肌梗死的鉴别诊断要点。
