kill two birds with one stone

kill two birds with one stone  {v. phr.}

Преуспеть в выполнении двух дел одним действием; получить оба результата при одном усилии.

Mother stopped at the supermarket to buy bread and then went to get Jane at dancing class; she killed two birds with one stone.

The history teacher told us that making an outline kills two birds with one stone; it makes us study the lesson till we understand it, and it gives us notes to review before the test.

Ср.: убить двух зайцев