答案：C

题目分析：从信息词 Otherwise可以看出是一个含蓄条件句，再从动词worked 可以看出是与过去相反，故主句使用would have been。本句可以改写为if引导的条件状语从句：if my father hadn’t worded day  and night,there would have been no one to support the family.

点评：含蓄条件句将条件隐含在某些连词(如or, or else, otherwise等)中。还有将条件隐含在介词短语中（如with ,without,but for等）。

即学即练:But for the help of my English teacher, I ______ the first prize in the English Writing Competition. A. would not win    B. would not have won   C. would win  D. would have

选B