当机立断
Fish or cut bait
Take the bull by the horns.
To think on one's feet.
Quick to act.

eg：Take action at this critical moment should be a to fish or cut bait decision.

中英俚语俗语来源：文选·陈琳·答东阿王笺：“拂钟无声，应机立断。”

同义词：快刀斩乱麻 Cut the Gordian knot.
反义词：犹豫不决 To shillt-shally.