I was so busy reading the book that I forgot to get off the bus at the stop.
我忙着看书所以忘记到站下车为什么填 to get?forget to do sth 表示忘记去做某事forget doing sth 表示忘记做过某事forget 后面只有这两种搭配这里根据题意应该是忘记去做某事