题目

Later,these rocks proved that___in the distant past the Antarctic was covered by plants.
A.at one time B.at a time C.at times D.at the same time

提问时间：2020-10-05

答案

答案：A
A.at one time 一度,从前
B.at a time 依次
C.at times 有时
D.at the same time 同时