A. once B. whileC. since D. unless

【C12】A．thenB．whileC．sinceD．where

答案解析

【C15】A．WhenB．WhileC．AsD．Unless

答案解析

______I was talking to Barbara, I learned that Tony was in hospital.A．UnlessB．WhileC．Since

答案解析

You’ll have more chances of promotion ______ you work hard.A、sinceB、whileC、asD、once

答案解析

【C2】A．WhileB．AsC．SinceD．Unless

答案解析

___________[A] Since [B] If [C] Unless [D] While

答案解析

_________(59)A.unless B.ifC.as D.since

答案解析