make hay while the sun shines; strike while the iron is hot ❍ 常言说，“～”，你怎么能这么犹豫不决呢？ As the saying goes，“Strike while the iron is hot.” How can you shilly-shally like this?
时不可失shí bù kě shī
时：时机；失：失去。紧紧抓住有利时机，不可错过。there is no time to lose, strike while the iron is hot, Now for it!