1. Measles is a highly infectious disease that spreads easily among unvaccinated individuals.
麻疹是一种高度传染性的疾病，易于在未接种疫苗的人群中传播。
2. Her laughter was infectious, and soon everyone in the room was laughing along.
她的笑声很具感染力，很快房间里的每个人都跟着笑了起来。