美国学生使用避孕用品的比例增加一倍

cigarette – n. a rolled paper product that has the drug nicotine

marijuana – n. a drug that creates a feeling of being "high"

vaping – v. to breathe the gas produced by an electronic cigarette

flash drive – n. a small device used to store electronic data

grade – n. a class organized for the work in a given year or a study program

senior – n. a student in the final year of a study program

epidemic – n. a product of sudden growth or spread; a disease or condition that affects many people at the same time