例1:I have a pen.I have a pen.have用于除第三人称单数外的人称实义动词,变否定句不能在have后加not,则需要助动词来帮助解决.do+not= don’t.例2:My father has a watch.My father doesn't have a watch.has 用于第三人称单数外的人称实义动词,变否定句不能在has后加not,则需要助动词来帮助解决.does+not=doesn't 注:变第三人称单数是,要注意动词部分的还原.