A.He knew this beforehand.B.He judged from his common sense.C.He judged from the speed

外语类 公共英语 已帮助 人

A.He knew this beforehand.

B.He judged from his common sense.

C.He judged from the speeds of sound

D.He judged by reading the textbook.

热搜:a是b的充分条件,b是a的必要条件吗