油泵转速过低的原因是什么？
参考答案：
油泵转速过低的原因有：皮带打滑，连轴器或电动机有故障。
The fact that so many people still smoke in public place _____ that we may need nationwide campaign
to raise awareness of the riks of smoking. [ ]
A. suggest
B. suggests
C. suggested
D. suggesting
试述风险识别的方法及其局限性。
