We are in a city where more than 90 percent of the population has defenses against the measles, which means that they either had the disease, survived, and developed natural defenses; or that they had been immunized against measles.
我们在一个城市 这里百分之九十的居民 都对麻疹有免疫力，这也就意味着 他们要么曾经得过麻疹并活了下来， 产生了自然的免疫力 要么已经接种过疫苗并对麻疹产生了免疫力