guinea pig
noun [ C ] uk/ˈɡɪn.i ˌpɪɡ/ us/ˈɡɪn.i ˌpɪɡ/
(ANIMAL)
豚鼠，天竺鼠
a small animal covered in fur with rounded ears, short legs, and no tail, often kept as a pet by children
(TEST)
（通常用于测试药效的）实验对象，供做实验的人
a person used in a scientific test, usually to discover the effect of a drug on humans
They're asking for students to be guinea pigs in their research into the common cold. 他们正在找学生来做他们研究普通感冒的实验对象。