(2017河北34题)Mom won't let Dick go out ________ he promises to be back by 10：00 tonight.
A.if B.when C.since D.unless
Bob, dinner is ready. Please wash your hands ________ you eat.
A.until B.after C.while D.before
I like dancing, ________ I don't have enough time to practice it.
I didn't know anyone at the party, ________ I felt a bit lonely.
Smile to the world, the world will smile back to you.
A. or B. and C. so D. but
My arm is still painful, I'm going to see a doctor.
A.so B.for C.but D.or
