一yī箭jiàn双shuāng雕diāo

Literal: one arrow, two eagles
Figurative: To achieve two goals with a single action; to kill two birds with one stone.

Where does 一箭双雕 come from?

Zhangsun Sheng, an officer of the Northern Zhou dynasty, was an archer of remarkable skill. Around the year 580 he was sent as an envoy to the Tujue (Turkic) people, escorting a princess to be given in marriage to Khan Shetu; there he so won the khan's trust that he was kept at his side and invited to hunt with him. One day they saw two eagles in the sky fighting over a piece of meat; the khan handed Zhangsun Sheng two arrows to bring them down. He took just a single arrow, waited for the two birds to line up, and with one shot pierced them both. From that feat the saying was born. (Zhangsun Sheng would later become a famous general and diplomat under the Sui dynasty.)

Source (出处): 《北史·长孙晟传》

How is 一箭双雕 used? Two examples

周zhōu末mò去qù爬pá山shān既jì能néng锻duàn炼liàn身shēn体tǐ又yòu能néng放fàng松sōng心xīn情qíng真zhēn是shì一yī箭jiàn双shuāng雕diāo。
Hiking on the weekend lets you exercise and relax at the same time; it really is killing two birds with one stone.
看kàn美měi剧jù学xué英yīng语yǔ一yī箭jiàn双shuāng雕diāo又yòu开kāi心xīn又yòu能néng提tí高gāo水shuǐ平píng。
Learning English by watching American shows kills two birds with one stone: it's fun and it improves your level.

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