变形形式：

1．一般情况下，直接加-s，如：cook-cooks, milk-milks

2．以s. x. sh. ch. o结尾，加-es，如：guess-guesses, wash-washes, watch-watches, go-goes

3．以“辅音字母+y”结尾，变y为i,再加-es，如：study-studies