1．Time waits for no man. But teenagers wont realize the value of time until its gone. Dont waste your time, you will regret it.
A. and B. or C. but
2．-Shall we get off the bus here?
-Yes. But we wont get off _______ it stops.
A.when B. until C. while D. after
3．-Susan, what are the advantages of MP5 players?
-Mom, they are smaller and lighter ______ they can be carried very easily.
A.unlessB.if C.untilD.so that
4．Think it over, _____ youll work out the math problem.
A. or B. so C. for D. and
5．Nobody will help you________ you help yourself.
A. unless B. because C. though