题目

—Would you like to tell me what our teacher said just now? —She said that light__________faster than sound. A.travels B.traveled C.would travel D.was traveling 答案：A 解析: 表示客观真理常用一般现在时。遵守实验室规则，学习基本的实验操作方法，是实验成功的重要保证。下列实验操作不正确的是