1 The radio is listened to by millions of people every day.
listen是不及物动词,听广播必须是listen to the radio,不管语序怎么变,这个to必须要有的
2 An English speech will be given to the children tomorrow
要用被动,英语报告不能给孩子们,只能被给
3 I have a lot of chores to do today.
主语+ have sth to do 固定搭配,表示有.要去做
这里to do是主动表被动的
4Newspapers are read every day at home,in offices and on trains
报纸不能读,只能被读,所以是被动