问题
选择题
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
答案：B
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。