a reply, he decided to write a sixth letter.
A. Not receiving
B. Not to receive
C. Not having received
D. Having not received
网友回答
A. Not receiving
B. Not to receive
(答案→)C. Not having received
D. Having not received
解析：非谓动词表示的动作如果发生在句子谓语动词表示的动作之前，非谓语动词就要用完成体。