put on the back burner字面意思可以摆在炉子的后边，引申为放在次要位置。

【例句】
The whole project has been put on the back burner.
整顿工程已久置于放在次要位置。

Plans for a new sports complex have been put on the back burner.
修建一座体育馆的计划不得不延后。