问题补充：
Lately some scientists are experimenting white mice to this kind of medicine.
A. on,try on
B. with, test on
C. on ,test out
D. with,carry out
答案：
A. on,try on
B. with, test on
(答案→)C. on ,test out
D. with,carry out
解析：句意：最近一些科学家正在在白鼠身上做实验来检测这种药。短语：experiment on 在什么上做实验，test out 检测，测试，所以选C。
