Re: by tomorrow morning
In the first pair, the second is possible, but not nearly as natural. It means he is not married now, but his state of being unmarried will change before tomorrow morning.
Originally Posted by ostap77
In the second pair, both are possible.
I need this finished immediately! Tomorrow afternoon is too late.
- Don't worry, it will be built by tomorrow morning.
So tomorrow when we get to Roaring Brook, we'll have to wade across, since the bridge still isn't finished.
- Oh, no, don't worry. It will have been built by tomorrow morning, a few hours before we are scheduled to get there.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.