问题补充:
Sandy went to Tibet by train this summer for the first time. She had an unusual .
A. experience
B. experiment
C. knowledge
D. condition
答案:
(答案→)A. experience
B. experiment
C. knowledge
D. condition
解析:experience经验,经历;experiment实验,尝试;knowledge 知识,学问;condition条件,环境。句意:这个暑假桑迪第一次乘火车去了西藏。她有一段不寻常的经历。结合语境可知选A。