have sth done与have sb do sth与 have sb doing sth区别

have sth done 让别人去做这件事,(某件事被做)e.g.I'll have my hair cut.我打算去理发.have sb do sth.让某人做某事,have是使役动词,后边要省略动词不定式tohave sb doing sth.让某人持续做某事,强调"持续"e.g.He h...