—Where did you get these old doors?

—From the old houses which were ______ by the workers.[ ]

A. taken down    

B. pulled down  

C. turned down  

D. put down

1976年8月16日，地处四川省西北部的松潘－平武地区发生了（）地震。

A.7.2级

B.7.6级

C.7.8级

D.8.0级