Definition
used to advise someone not to expect something to happen soon, suggesting that it may take a very long time.
別期望了，不可能發生。
They said they would fix the machine soon, but don't hold your breath.
他們說會很快修好機器，但別抱太大希望。
He promised to help me move, but don't hold your breath about him being on time.
他答應幫我搬家，但別指望他會準時。
The government says they will address the traffic problem, but don't hold your breath for major changes.
政府說他們會解決交通問題，但別指望會有重大改變。