Wait a minute
This is pretty generic and informal and is often used idiomatically to ask someone to pause what they're doing until told to continue. It doesn't usually mean exactly a minute, any more than "wait a second" means exactly a second.
Wait for a minute
This sounds like something that you'd find in directions/instructions:
Wait for a minute and then add the oil to the pan.
In this case, it more often means exactly a minute, though it's not required. The exact timing here is more important. You would be unlikely to find native speakers who would use this in the idiomatic manner of the previous example.
Now, does this carry over to numbers of minutes greater than one? Sort of?
Wait five minutes
Will usually mean five actual minutes... otherwise, why bother specifying the number. As mentioned before, "wait a minute" doesn't really mean a minute... one could end up waiting for a few seconds or several minutes in the end. Even in directions, you'll often find they've left out the "for" in this case:
"Remove from stove after one minute of boiling and wait five minutes before topping with granola."
So what about with the "for"?
Wait for five minutes
This isn't wrong. Using it this way is not ungrammatical at all, it's your choice. It's not required and you will definitely find examples of it, particularly in more professionally-written instructions:
Slide the whole skillet under the broiler, and wait for five minutes, until the crumbs are golden brown and the salmon is done.
This is also discussed, though not to a great degree, in Cambridge Dictionaries Online:
Wait means ‘stay in the same place or not do something until something else happens’. We can use it with or without for:
- Put a tea bag into the cup, then add water and wait (for) a minute or two before taking it out.
- I phoned the head office but I had to wait (for) five minutes before I spoke to anyone.
To
give a dinner for
implies it is an honorary dinner, even in your first example.
...gave a dinner for the Shah ( in honour of )
...gave a dinner in honour of the Shah ( obvious meaning )
...had dinner with the Shah ( maybe just grabbed a bite to eat )
Doing something in honour of someone, is to do something for someone with a feeling of respect. To do something for someone does not necessarily mean the feeling of respect is involved.
In your example, giving a dinner to someone is to physically hand dinner over to them. Giving a dinner for someone means you are celebrating something and allows you to participate with them.
Best Answer
The preposition is optional there. Said that, it depends on the writer's style.
OALD has an entry for it:
However, I would not have had this idea, had I not seen that entry some months back. Still, I prefer using the preposition to satisfy myself!