from now是從現(xiàn)在開(kāi)始,不屬于固定搭配,from后面加時(shí)間表示從什么時(shí)候開(kāi)始……,比如,I have to do my homework from now(我不得不現(xiàn)在開(kāi)始做作業(yè)了)也可以用其他時(shí)間,比如"I started learning Korean from the year of 2008"(我2008年開(kāi)始學(xué)韓語(yǔ)的)
而from now on是一個(gè)固定搭配,是“從今以后”的意思,有一種決心在里面.比如“From now on,I won't go to play footbal at night,I promise."(我發(fā)誓從今以后再也不在夜里踢足球了.)