问题补充:
he has been blind since birth, Joseph Chadbourne never feels different from his class-mates at school.
A. Since
B. Once
C. Unless
D. While
答案:
A. Since
B. Once
C. Unless
(答案→)D. While
解析:考察连词辨析。A既然;自从;B一旦;C除非,如果…不…;D尽管;当…时;然而;句意:尽管出生时就看不见了,但是Joseph Chadbourne从未感觉到自己与学校的同学有什么不同。根据句意说明D正确。考生要特别注意连词的一词多义现象。