Flowers fall off [will die], do what one may. Swallows return, no strangers they.

无可奈何花落去, 似曾相识燕归来。

《新英汉大辞典》

Swallows return should be back to rain, the first twelve lines on the bead curtain.

雨来双燕归应早，先上珠帘十二行。

youdao

Swallows may have gone, but there is a time of return; willow trees may have died back, but there is a time of regreening; peach blossoms may have fallen, but they will bloom again.

燕子去了，有再来的时候；杨柳枯了，有再青的时候；桃花谢了，有再开的时候。

youdao

Swallows may have gone, but there is a time of return; willow trees may have died back, but there is a time of regreening; peach blossoms may have fallen, but they will bloom again.

燕子去了，有再来的时候；杨柳枯了，有再青的时候；桃花谢了，有再开的时候。

youdao