1. ________ he comes, we won’t he able to go.
A. Without B. Unless
C. Except D. Even
答：B。unless“除非，如果不”，为连词，相当于于if...not。even为副词。A和C项为介词。
2. I didn’t manage to do it ______ you had explained how.
A. until B. unless
C. when D. before
答：A。若选B项主句应是虚拟句式 I wouldn’t have managed to do it if you had not explained how.
