Originally Posted by Tooba Malik

according to my knowledge which is not perfect
1st sentence is called conditional sentence as there is given a condition and its method of structure that there are 2 parts of sentence one has condition and 2nd part is reaction .so in condtional part had is used with 3rd form of verb and in in 2nd part would have is used.e.g
agr tm mahnat krty to pass ho jaty
if you had worked hard .you would have passed examination.
so here had is used but not been
2. Had there been better communication, this may not have occurred!
here been is as a main verb not as a auxiliary verb. been is third form of was .
http://www.ego4u.com/en/cram-up/gram...onal-sentences
check this link too.