短语词组短语plod on 沉重地向前plod tread 走的词根plod 2 赖氨酸羟化酶基因snow plod 轻而易举登上雪山flit plod 迅速飞过plod detail 努力用功Plod Away At One 's Work 胼手胝足plod one 's weary way detail 长途困顿 返回 plod