It seven years Hong Kong returned to China.
A. was, since
B. is, since
C. was, after
D. is , after
网友回答
A. was, since
(答案→)B. is, since
C. was, after
D. is , after
解析：考查时态及连词辨析.句意:自从香港回归中国以来有七年了.结合语境可知本句描述的是客观性动作,故用一般现在时态.since自从……以来，after在……之后，固定搭配It is+段时间since +句子，意思为：自从……已多长时间了,结合语境可知选B.