According to the latest research, getting enough sleep is _____ to maintaining good health and reducing stress.
This is the very room ______ I slept in that evening.
We talked about the things and persons ______ we remembered at school.
John said he’d been working in the office for an hour, ______ was true.
New York, ______ last year, is a nice city.
You can take any book ______ interests you best.