问题补充:
around Tian’anmen Square, the tourists were taken to visit the Palace Museum.
A. Showing
B. Having shown
C. Being shown
D. Having been shown
答案:
A. Showing
B. Having shown
C. Being shown
D. Having been shown
解析:the tourists与show是被动关系,show发生在谓语之前,用完成式。