Duìzhàozǔ de xiǎoshǔ méiyou yòngyào, tǐzhòng jīhū méiyou biànhuà.
The mice in the control group got no drug, and their weight barely changed.
Tips
usage
Its partner is 实验组, the experimental group. In drug trials the control group is often given a 安慰剂, a placebo, so that nobody can tell which group got the real treatment.