n.沖動；激勵；原動力

I felt the impulsion to ask her to stay. 我心里有股沖動

Faith is the impulsion, the propulsion of this power within. 信念是一種激勵，是對你內(nèi)心巨大能量的一種激勵。

Interaction of parts is the impulsion to keep flourish of the Earth. 零件與零件之間的互動，就是維持這個地球生機(jī)盎然的原動力。