1.the doctors have done everything they can _____the man's l

1.the doctors have done everything they can _____the man's life.
A.save B.saving C.to save D.for saving
2.last night he was caught ______a heavy rain and was wet _____when he got home.
A.by,to B.in ,through C.with,by D.with,in
3.breathing equipment_______protecting firemen from smoke.
A.used to B.is used for C.is used to D.ues to
4.she must be in her room,_____?
A.isn't she B.is she C.mustn't she D.needn't she
5.the great wall will stop the sand _____blowing_____the rice farmland in the south.
A.for,to B.for ,towards C.from,for D.from,towards