nim.bo.stra.tusn.(名词)【复数】 nim.bo.stra.ti[-str3.to, -str2t.o] A low, gray, often dark cloud that precipitates rain, snow, or sleet.雨层云:一种呈深灰色的低云层,预示有雨、雪或冻雨来源:nimb(us) nimb(us)stratus stratus