单选题 He meant telling us about it, but he forgot to tell us.
A. to be telling B. telling C. to have told D. having told

【正确答案】 C

【答案解析】[解析] 在此表示“忘记做某事”，应用动词不定式。且动词不定式所表示的动作发牛在谓语动词“忘记”这个动作之前，应用to have told us。因此C为答案。