Clauses Stating Reasons and Conditions
Drivers can fall asleep on the highway _____ they rest before long trips. (unless / only if / considering that)
unless
Power naps at work are a good idea, _____ you have your boss's OK. (unless / as long as / just in case)
as long as
Some people set two morning alarms _____ they sleep through one. (considering that / only if / in case)
in case