Basically, one indicates scale, the other indicates methodology. These are from wiktionary. Depending on use they might be somewhat interchangeable. It would seem redundant to use both, yet some...
Concrete thinking is more on the surface, something that you point out or think of is more obvious. Abstract thinking is something more under the surface, something that is deeper in thinking, like...
There is not much difference. They can, in fact, mean the same thing, but "thinking of you" is used more when one is thinking about what would please or help the other person. "When I saw your...
It's means "it is" Its' means "belonging to it". Example:We went to see a Chicago landmark. It's downtown and quite popular. Over a million visitors a year attest to its' popularity.