Scientists from two laboratories plan to conduct tests of unusual precipitation that fell across the region in hopes of pinpointing the origins of so-called "milky rain" that has mystified residents. 

来自两家实验室的科学家计划，化验西北地区降下的不同寻常的、令居民感到困惑的所谓“牛奶雨”的沉淀物，希望准确地找出其来源。

Officials at both the Pacific Northwest National Laboratory and the Benton Clean Air Agency, both in Washington state, said they had collected samples of the rain, which left a powdery residue on cars across a wide swath of two states. 

位于华盛顿州的美国西北太平洋国家实验室和本顿清洁空气机构的官员称，已采集了“牛奶雨”的样本。这种雨水给两个州很多地区的汽车上蒙上一层粉末状残留物。

Scientists at the Pacific Northwest Nationallab said they believe the rain may have carried volcanic ash from an erupting volcano in Japan, while Benton Clean Air said its staffers believe dust from central Oregon was the culprit. 

西北太平洋国家实验室的科学家们称，他们认为“牛奶雨”可能来自日本一座火山喷发出的火山灰。本顿清洁空气机构则表示，他们的科学家认为，俄勒冈州中部地区的灰尘是罪魁祸首。