jot something down
phrasal verb with jot verb [ T usually + adv/prep ] uk/dʒɒt/ us/dʒɑːt/ -tt-
匆匆记下，草草记下
to write something quickly on a piece of paper so that you remember it
I carry a notebook so that I can jot down any ideas. 我随身带了个笔记本，这样可以把想法随手记下来。