每日一词 2177 effective

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，今天我们的词是 effective, effective, effective...