There was a whine of hydraulics as the undercarriage locked into position.随着液压系统嘎吱一声响，起落架进入了锁定位置。The undercarriage on light aircraft does not always retract in flight.轻型飞机飞行时起落架不一定缩回.A kind of cutter undercarriage mechan...
工程学和工艺学互不相同，也有别于自然学科。Engineering and technology are disciplines distinct from one another and from science.这些公司将大量资金投入生物工艺学研究, 尤其是药品和新种子方面.The companies are pouring trillions of yen into biotechnology research, especiall...