The paper investigated the maintenance and service of the equipment and introduced the harm of oil pollution, over oil temperature and airinvasion and their counter measures.
本文就其在运行中如何加强维护与保养作些探讨，介绍油液污染、油液过温和空气侵入的危害及应对措施。
2
The Normandy invasion began with overnight parachute and glider landings, massive air attacks, naval bombardment.
诺曼底登陆开始于连夜的降落伞和滑翔机着陆、大规模的空袭、海军轰炸。
3
After Hamas stepped up its rocket attacks at the end of 2008, Israel began a major offensive in the Gaza Strip, launching air strikes and a ground invasion.