动词三单的变化规则1一般情况下，直接加-s，如：cook-cooks, milk-milks2以s. x. sh. ch. o结尾，加-es，如：guess-guesses, wash-washes, watch-watches, go-goes3以“辅音字母+y”结尾，变y为i, 再加-es，如：study-studiesbe动词的过去式为was, were；行为动词的过去式有规则变化和不规则变化两种，规则变化有以下几种情况：1）直接在动词原形末尾加-ed. e.g. work-worked; ask-asked; 2）以e结尾的动词只加-d. e.g. arrive-arrived; like-liked.3)末尾只有一个辅音字母的重读闭音节,应先双写这个辅音字母,再加-ed. e.g. shop-shopped; 4)以辅音字母+y结尾的动词,先把y变成i,再加-ed. e.g. carry-carried; study-studied.有些动词变过去式是不规则
