Is it correct to write:
"He knew he'd be back in a couple hours"?
Or should it be:
"He knew he'd be back in a couple of hours"?
Or does it depend on whether it's American or English literature?
"He knew he'd be back in a couple hours"?
Or should it be:
"He knew he'd be back in a couple of hours"?
Or does it depend on whether it's American or English literature?