kill two birds with one stone
succeed in doing two things by only one action一箭双雕
Mother stopped at the supermarket to buy some bread and then went to get Jane at the dancing class； she killed two birds with one stone．妈妈在超级市场买了些面包，然后去舞蹈训练班接简回家，她一举两得。
“When you're next in London，come and see me．”“Yes， I'll do some shopping and kill two birds with one stone．”“下次你来伦敦时就来看看我。”“当然，我还将买点东西，一举两得嘛。”