Sorry, Tom, I forgot ________ the door before I left, but I do remember ________ the key to the door keeper.
句意:抱歉汤姆,我走之前忘记锁门了,但是我记得把钥匙还给门卫了。这里考查forget和 remember的用法。forget和remember后面接to do时表示忘记(或记得)要去做某事,后接doing时表示忘记 (或记得)做过某事。故选B。