qíng lǎng / de / tiān qì / lǐ / ， / fēi jī yún / néng / zài / gāo kōng / tíng liú / hěn cháng / shí jiān / ， / tè bié / míng xiǎn / 。

晴朗的天气里，飞机云能在高空停留很长时间，特别明显。

In clear weather, contrails can stay in the high altitude for a long time, which is very obvious.