问题
选择题
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
答案：C
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。