impetus
noun [ S or U ] uk/ˈɪm.pɪ.təs/ us/ˈɪm.pə.t̬əs/
推动，促进，刺激
something that encourages a particular activity or makes that activity more energetic or effective
The recent publicity surrounding homelessness has given (a) fresh impetus to the cause. 最近围绕无家可归者的宣传对这一事业是个新的推动。