比喻突然产生某种念头，冲动prompted by a sudden impulse; tide of heart's blood

• 银川市委开展的结对共建活动，并非一时心血来潮。

  The paired construction activity initiated by the Yinchuan municipal committee was not prompted by a sudden impulse.

• “处处为他人着想”并不是一时心血来潮就能办到的。

  "thinking of others at every step" is not something one can do on a whim.