今天我们要学的词是roller coaster。 Roller coaster, 是翻滚过山车的意思，可以用来指事件和情绪的时起时落，忽好忽坏。 "NBA star Kobe Bryant is having a roller coaster year," 美国篮球明星布赖恩特今年可以说是大起大落。 "It's a roller-coaster of emotions for the plane crash survivors," 坠机事件幸存者的情绪大起大落，很不稳定。 "Wall Street scored a small gain after a roller-coaster day," 华尔街当天的股票价格大起大落，最后收盘时小幅上扬。好的，今天我们学习的词是roller coaster...