Studying in groups is necessary _________________ you want to do well in school.
A.if B.until C.unless D.though
Eric arrived on time, _______ it was the rush hour.
A. though B. because C. while D. unless
(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.
