The Blacks moved to Beijing.A. last week agoB. a week agoC. a week beforeD. in a week

问题补充：

The Blacks moved to Beijing.

A. last week ago

B. a week ago

C. a week before

D. in a week

答案：

A. last week ago

(答案→)B. a week ago

C. a week before

D. in a week

解析：句意：布莱克一家一周前搬到了北京。in a week，一周后；一周前，a week ago。故选B