want to do想做某事,want意思是“想要”,主语常是人
want doing 需要做某事,want意思是“需要、要求”,主语常是物want to do很常见,无需举例.
给你一个例句：The plants want watering daily.这些花草得天天浇水.
need to do 需要做某事,表示主动,主语一般是人
need doing 某物/事需要…,表示被动,主语常是物.
给一个例句：The garden doesnit need watering—it rained last night.花园不用浇水了—昨夜刚下过雨.