Because bacteria are invisible to the () eye, it was only relatively recently in human history that we even became aware of their existence.
A.naked
B.bare
C.common
D.natural
正确答案:naked
Because bacteria are invisible to the () eye, it was only relatively recently in human history that we even became aware of their existence.
A.naked
B.bare
C.common
D.natural
正确答案:naked