tiān qì / qíng lǎng / shí / tiān kōng / zhōng / de / juǎn yún / cháng / chéng xiàn / xì cháng / de / yǔ máo zhuàng

天气晴朗时，天空中的卷云常呈现细长的羽毛状。

When the weather is clear, the cirrus clouds in the sky often appear as slender, feather-like streaks.