0 to speak quietly and in a way that is not clear so that the words are difficult to understand -- 含糊地說,咕噥
She mumbled something about being too busy. 她嘟囔著說太忙了。
[ + speech ] "I'm sorry," he mumbled. 「對不起,」他咕噥道。
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
再长的路,一步步也能走完,再短的路,不迈开双脚也无法到达。