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
Put on your coat, you will catch a cold.
A.and B.but
C.or D.so
Tommy, don't make a noise! ________ you have any questions, please put up your hands.
A.Before B.If C.Though D.Until
My mother was cooking in the kitchen ________ I came home.
A.after B.while C.when D.until
(2018邢台二模) You'd better bring a sweater ________ it is cold there in the evening.
A.unless B.because C.when D.if
