nplayer使用教程:sth must to be done什么意思

sth must to be done什么意思 have sth to be done和have sth done的区别是什么？ Sth.to do 和 Sth.to be done 有什么区别联系啊？？ let sth be done and let sth done 的区别 Repairs must be done to this road.这句话怎么解释？？？？？？ be sth to sb . All that must be done _______________(do). To be ,to be done什么意思? being done, done ,to be done的区别 be used to doing sth?