问题补充:
Scientists have found no of life on Mars so far,though great efforts have made on the research.
A. symbols
B. signs
C. marks
D. signals
答案:
A. symbols
(答案→)B. signs
C. marks
D. signals
解析:signs 迹象;symbols 象征;marks 标志;signals 信号。
时间:2019-06-17 17:59:07
Scientists have found no of life on Mars so far,though great efforts have made on the research.
A. symbols
B. signs
C. marks
D. signals
A. symbols
(答案→)B. signs
C. marks
D. signals
解析:signs 迹象;symbols 象征;marks 标志;signals 信号。