C) brought(带来) D) taken(拿走，占领， 获得， 接受)
It is possible(可能的) that aliens have worked out (设计出， 计算出，可以解决)how to travel(旅行) through(穿过) space. Yet some people report(报告) that they have been taken by (被带走)aliens and have had experiments(实验， 做实验) __15__ on them.
15.A 根据空格所在的局部结构“have had experiments.。。on them/使实验在他们身上被。。。”判断A(做)是答案。
考点：非谓语动词结构/常见动词的辨析
Why would anyone(任何人) travel across(越过) half(一半的， 一半， 部分地) the universe(宇宙) to conduct(做，管理) medical(医学的) experiments on people living(生活， 活的，起作用的) in small(小的) towns(城镇) in the United States(美国)？