to take my English textbook, I had to borrow one from a schoolmate.
A. Forget
B. To have forgotten
C. Forgotten
D. Having forgotten
网友回答
A. Forget
B. To have forgotten
C. Forgotten
(答案→)D. Having forgotten
解析：考察分词用法。I与forget构成主动关系，且忘记带英语书是在谓语动词借书之前，所以使用完成式，故D正确。