今天我们要学的词是effective. Effective,有效的。The U.S. Center for Disease Control and Prevention says this year's flu shot is less effective because the current flu virus has mutated. 美国疾病预防和控制中心说,由于流感病毒变异,今年流感疫苗的防疫效果可能不是很有效。Indonesia has developed a male birth control pill that is 99% effective. 印度尼西亚开发出了一种男用避孕药,有效率高达99%。好的,今天我们学习的词是effective, effective, effective...
n. 克制,控制,管制,操作装置
vt. 控制