Question

【題目】Don't call me at the office ________ it is necessary.
A.before
B.unless
C.although
D.till

Answer 1

【答案】B
【解析】考查連詞。句意：請不要打電話到我的辦公室，除非是真的有必要。A. before在……以前；B．unless除非，引導條件狀語從句；C. although盡管；D. till直到……為止。故選B。