How do you think of these?
" 1.If Rechard was at the recepion last night, he must have been presented to the president.
2.If Rechard spoke at the recepion last night, he must have been presented to the president."
I don't think they are right.(EC86.5.20),because they expressed facts opposite to the past. If 1. is right, so is 2.
The use of "If he was there" only suggests that either the speaker doesn't know for sure that he was there, or that someone else has said he was there and the speaker is making an assumption based on that statement.
If A is true, then B must be true.
If the speaker knew for a fact that Rechard wasn't at the reception, he would have said:
If Rechard had been at the reception, he would have been presented to the president.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Thank you !