I am not sure I agree with you here:-(I am not a professional teacher. The prolem here is the proper usage of inifinitive. hsb will do well to visit a site on gerund and infinitive. My observations are as follows.
A- I was to go. It is not correct to use an infinite after an auxiliary verb.
D- I was to have gone. This is grammatically incorrect.
If you take a look at David's examples you should be able to see that all of them work.;-)Thank you very much all of you for replying.
What I actually want to know is if I want to say that I had decided/planned or had an intention to go somewhere but I did not go or could not go which of the above sentences should I use? Please help me.