________ you make a promise, you should try to keep it. Or you'll lose others' trust.
A.Unless B.Because C.Before D.Once
________ we finished drinking tea, we all sat on the grass.
A.When B.After C.Before D.If
Tom is only two years old, ________ he shouldn't be left alone.
A.and B.so C.but D.for
________ he has said sorry to you, please give him another chance.
A.When B.Since C.Before D.Until
Jane, please turn off the lights ________ you leave the classroom.
A.after B.before C.until D.unless
I am quite busy. I don't know ________ I'm free or not tonight.
A.if B.unless C.whether D.when
