This idiom means achieving two things with one action.
Chūnqiū shíqī Jìnguó xiǎng gōngdǎ Guóguó
春秋Chūnqiū🔊时期shíqī🔊，晋国Jìnguó🔊想xiǎng🔊攻打gōngdǎ🔊虢国Guóguó🔊。
Qù Guóguó bìxū jīngguò Yúguó
去Qù🔊虢国Guóguó🔊必须bìxū🔊经过jīngguò🔊虞国Yúguó🔊。
Jìnguó yòng bǎomǎ hé měiyù huìlù Yúguó jièdào gōngdǎ Guóguó
晋国Jìnguó🔊用yòng🔊宝马bǎomǎ🔊和hé🔊美玉měiyù🔊贿赂huìlù🔊虞国Yúguó🔊，借道jièdào🔊攻打gōngdǎ🔊虢国Guóguó🔊。
Mièdiào Guóguó hòu Jìn jūn huíshī túzhōng yòu mièdiào le Yúguó
灭掉Mièdiào🔊虢国Guóguó🔊后hòu🔊，晋军Jìn jūn🔊回师huíshī🔊途中túzhōng🔊又yòu🔊灭掉了mièdiào le🔊虞国Yúguó🔊。
Zhè jiùshì yī jǔ liǎng dé
这Zhè🔊就是jiùshì🔊一举两得yī jǔ liǎng dé🔊。
English Translation:
During the Spring and Autumn period, Jin wanted to attack Guo. To reach Guo, they had to pass through Yu. Jin used fine horses and beautiful jade to bribe Yu, borrowing a route to attack Guo. After destroying Guo, on their return march, Jin also destroyed Yu. This is achieving two things with one action.