问题补充:
It is said that the old coins under the earth for about 100years by the time they were discovered.
A. had buried
B. had been buried
C. buried
D. were buried
答案:
A. had buried
(答案→)B. had been buried
C. buried
D. were buried
解析:考查时态。by the time+过去的时间,主句用过去完成时态,根据by the time they were discovered.,应选B。句意:据说这些古老的硬币被发现的时候,已经被埋在地下100年了。