Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
transmission – n. the act or process by which something is spread or passed from one person or thing to another
mosquito – n. a small flying insect that bites the skin of people and animals and sucks their blood
repellent – n. a substance that is used to keep something out or away
condom – n. a thin rubber covering that a man wears on his penis during sex in order to prevent a woman from becoming pregnant or to prevent the spread of diseases
