1.to supersede; to replace; 2.to alternate with (or between); to take place by turns; to do sth. turn and turn about; to trade off是什么意思_1.to supersede; to replace; 2.to alternate with (or between); to take place by turns; to do sth. turn and turn about; to trade off在线翻译_英语_读音_用法_例句