【题目】It is said that the old coins under the earth for about 100 years by the time they were discovered.
A.had buried
B.had been buried
C.buried
D.were buried

【答案】B
【解析】这题考查动词的时态语态：金币是被埋葬，所以是被动式，而且时间是by+过去时间，所以用过去完成时的被动。选B。