问题补充：
It nearly two weeks I had received his letter.
A. is, that
B. was, that
C. is since
D. was, since
答案：
A. is, that
B. was, that
C. is since
(答案→)D. was, since
解析：since，for作为连词，引导时间状语（从句）如果谓语动词是延续性的一般过去时，其表达的含义是从这个动作结束以来，恰好和动词的词义相反，具有否定的含义；如果谓语动词是非延续性的一般过去时，其表达的含义是从这个动作开始以来，恰好和动词的词义一致，具有肯定的含义
