1、It was several minutes ____we realized what was happening-our dog was trapped in a newly-dug tunnel.
A.since B.before C.until D.while
2、She is ______ a teacher; she is also a writer who has written three boo ks.
A. not more than B. rather than C. more than D. no more than
3、The man we were following stopped from time to time ________ he was too tired to walk.
A.even if B.so that C.as if D.except that
4、The music, which used to _____ before the important meeting, has now been changed.
A.play B.playing C.being played D.be played
