【题目】________ around the beautiful campus, they were taken to the classroom to observe a maths lesson.
A．To be shownB．Having shown
C．Having been shownD．To show
在线课程【答案】C
【解析】
试题分析：句意：参观完美丽的校园后，他们被带去教室听了一堂数学课。句中动词发生有先后，先发生的在句中作状语，故用动词-ing形式的完成时；因为主语是they，与动词show是被动关系，故用被动语态，故选C。