Mrs Smith worked day and night he found it difficult to make enough money to support such

问题补充：

Mrs Smith worked day and night, he found it difficult to make enough money to support such a large family.

A. Since

B. If

C. Once

D. Although

答案：

A. Since

B. If

C. Once

(答案→)D. Although

解析：考查连词：A. Since自从B. If如果C. Once一旦D. Although虽然，句意：虽然斯密斯太太日日夜夜工作，但她发现很难挣足够的钱养活一家人。选D。