Even if he could build a computer out of what was obtainable, there would be no way to power it.
Even if it was possible for him to create a computer out of what he had, there would be no power source for it.
He knew he'd be able to power the computer, if only he could build one.
A girl is in the kitchen.
A man is outside.
A group of people riding a ferris wheel.
The woman is riding a bike.
A dog smells a tree stump.
Finally, I know about it.