1. The nineteenth century witnessed a revolution in ship design and propulsion. 19世纪经历了船舶设计和推进上的一次重大变革。
2. Propulsion is provided by a rocket engine, rather than a propeller and rudder, which makes steering difficult. 推进器是由火箭发动机提供的，而不是螺旋桨和方向舵，这使得转向变得困难。
3. Scientists and engineers are beginning to study this ability of fishes in the hope of designing more efficient propulsion systems for ships. 科学家和工程师们开始研究鱼类的这种能力，希望能设计出更有效的船舶推进系统。
4. Cerf has been working with NASA's Pasadena Jet Propulsion Laboratory—the people behind the recent Mars expedition—to design what he calls an "interplanetary Internet protocol." 瑟夫一直在与美国宇航局的帕萨迪纳喷气推进实验室（最近火星探测的幕后人员）合作，设计他所说的“星际互联网协议”。
5. The large hind legs were used for propulsion in water. 巨大的后肢用于在水中驱动。
