N-MASS
疫苗
A vaccine is a substance containing a harmless form of the germs that cause a particular disease. It is given to people, usually by injection, to prevent them getting that disease.
例句
Anti-malarial vaccines are now undergoing trials...
抗疟疾的疫苗正在试验阶段。
Seven million doses of vaccine are annually given to British children.
英国孩子每年要接种7百万剂疫苗。