We began to open to the outside world in the late 1970s. there have been great changes in

问题补充：

We began to open to the outside world in the late 1970s.,there have been great changes in the country.

A. As a result of

B. As a result

C. First of all

D. After all

答案：

A. As a result of

(答案→)B. As a result

C. First of all

D. After all

解析：考查固定词组，As a result of意思“……的结果”，As a result意思“结果”，First of all意思“首先”，After all意思“究竟”，句子意思“在上个世纪70年代末，我们开始对外开放，结果，我们国发生了很大的变化”，所以选B