— Do you know sound travels very fast?
— Yes. But light travels sound.
A. as fast as
B. a little faster than
C. much faster than
D. slower than
网友回答
A. as fast as
B. a little faster than
(答案→)C. much faster than
D. slower than
解析：在宾语从句中客观真理（光速比声速快得多）都用一般现在时。