Although it was not named _________ 1782, this kind of metal was used as early as 5300 BC．
Although it was not named _________ 1782, this kind of metal was used as early as 5300 BC．
A.in
B.for
C.until
D.since
答案及解析： C
Although it was not named _________ 1782, this kind of metal was used as early as 5300 BC．
A.in
B.for
C.until
D.since
答案及解析： C