明亮的流星，或者说陨石，是番难忘的景象。A bright shooting star, or meteor, is an unforgettable sight.约翰的魄力和热情最令人难忘。John will be best remembered for his drive and enthusiasm.参观博物馆是一段令人难忘的经历。A visit to the Museum is an unforgettable experienc...
轻型飞机飞行时起落架不一定缩回.The undercarriage on light aircraft does not always retract in flight.男孩看见那条蛇吓得猛地缩回.The boy started back in fear when he saw the snake.但是现在要缩回来当然为时已晚.But it was too late then, of course, to back out....