One third of the people trapped in the ruins at last.
A. has dug out
B. was dug out
C. have dug out
D. were dug out
网友回答
A. has dug out
B. was dug out
C. have dug out
(答案→)D. were dug out
解析：考察主谓一致。句意：陷入废墟中的三分之一的人最后被发现了。在有分数修饰的名词后，谓语与复数主语保持一致，本句中people表示复数人们的意思，人们是被发现的对象，故用被动语态，选D。