I wonder how many conditional sentences'sentence types are possible. Basically, there are four main and two mixed types. By mixing tenses, it could be up to nine of them. Are the rest viable? I
I came across the following examples in 'Full Spate Pre-Profficiency Primer'Full Spate Pre-Profficiency Primer:
After you have just sold alcohol to a young guy. If he is if under eighteen, you should not have sold him the alcohol.
If he promised to bring the drinks, he will.
If you will take a seat, the doctor will see you shortly. (Likely, the former will demonstrates politeness only.)
I would be grateful if you would tell me a little about your friends. (The same politeness, but would instead.)
If he will keep eating all those biscuits, he can not expect to stay as slim as he used to be.
I would be grateful if someone could shed more light on the topic.