Ok I have a few questions, my Italian is very patchy you see and while I can be confident in one area a much more simple area of my brain can be very patchy, so I just want to clarify I understand these things: I would go - Andrei - just changing the main verb into the conditional. I would have gone - Sarei andato - Just conjugating normal passato prossimo but putting the auxiliary in the conditional. I have to/must go - Devo andare - Addition of the verb 'dovere' I should go - Dovrei andare - This is where 'dovere' has to be put into the conditional. I had to go - Sono dovuto andare - Just the past version of 'have to'. I should have gone - Dovrei essere andato - This is where it gets confusing for me, looking at all the above and imagining what has to combine to get it right. Is it right? What needs to be done is to have the "Dovrei" again to represent "I should" like the "I should go" version, but it has to be in the past which means the infinitive isn't used (andare) but rather (andato) to express the past, and therefore because an infinitive comes after "dovere", it has to be the auxiliary 'essere'? I could go - Potrei andare - doesn't need explaining I could have gone - Potrei essere andato - This is just the other variation on using the modal verbs in the past, but replacing "dovere" with "potere" to express "could have" instead of "should have" ? Ok, what have I got wrong in this post? I was trying to remember a situation where one used the infinitive aux verb and one just used the conditional of a modal and my brain got a bit overworked, is it just using the modal verbs in the past, always means you need to use the infinitive auxiliary? I would appreciate it if the level of complexity didn't go beyond the level I am talking at now, not until I can post here and say I fully understand, I really don't want to confuse myself with people posting exceptions and little language nuances that are for advanced learners, not until I can say I understand the corrections I hope you can give me.