I have problems with these sentence which are requires to be filled by prepositions:
Questions:
1. He supported the idea at first, but backed
____________ when he found he'd have to contribute towards the cost.
2. He broke
__________ completely on hearing of his daughter's death.
3. You can't go back
______________ your promise now, we are depending on you.
4. The situation is difficult and calls
___________ great tact.
My Answers:
1. off
2. out
3. without
4. in
Well, please check this. If I am grammatically wrong, say "wrong, (your answer)"! If I am grammatically right but there is another suitable alternative say "right but more appropriate is (your answer)". If I am right, just say right

Thanks in advance!