1、have sth done表示的是，是某事被做，动作未必是我发出的。I had my bike mended.2、have sth to do，有事情要做，动作是我发出的。3、have sth to be done 意思是有某事将要去做. I have several exams to be taken next week. 下周我要考很多科试.
