国产精品永久免费视频- 无码精品A∨在线观看中文 -热re99久久精品国产99热-国产成人久久777777

cold front

最近兩天，隨著較強冷空氣的逐漸逼近，我國北方大部份地區的溫度急劇下降。請看報道： Residents of North China have to get their heavy woollens out from today with a cold front closing in and temperatures set to drop appreciably. Beijingers will feel autumn slipping away with the leaves blown away by increasingly cold winds. Winter will set in by the middle of next month. Cold front 的意思是"冷鋒"，即冷空氣氣團的前鋒部分。Front在氣象學中指的是"鋒"，也就是冷暖氣流的交界處。如：active front（活躍鋒），arctic front（北極鋒）。此外，"寒流"可表達為cold current. （中國日報網站編）