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

A．As a result of

B．As a result

C．First of a11

D．After all

下列物质的分离方法不正确的是（　　）

A．用过滤的方法除去食盐中泥沙

B．用蒸馏的方法将自来水制成蒸馏水

C．用酒精萃取碘水中的碘

D．用水冲洗的方法从沙里淘金