.Mr. Black has been teaching English in a middle school he came to China.A. for ever B. e

问题补充：

.Mr. Black has been teaching English in a middle school he came to China.

A. for ever

B. ever since

C. ever before

D. long before

答案：

A. for ever

(答案→)B. ever since

C. ever before

D. long before

解析：考查固定词组：A. for ever曾经，B. ever since自从，C. ever before以前，D. long before很久以前，句意：自从布莱克先生到中国来一直在中学教英语。和ever since+从句，连用的主语是现在完成时，选B。