it _to all that light travels faster than sound Ait _to all that light travels faster than soundA.is known B.is know C.know D.is said
问题描述:
it _to all that light travels faster than sound A
it _to all that light travels faster than sound
A.is known B.is know C.know D.is said
答
选C,强调客观的事实:光速比声速快是众所周知的