Knowledge can be created in an active dialogue among those who seek to understand and apply concepts. Most of Web-based learning systems provide a discussion forum to create knowledge. However, discussion forum posts are separated from the context of the learning activities. Students must manually rebuild the context of their questions before posting. Students also commented that they had problems interpreting the answers to the questions posted. This paper proposes an online e-book annotation interface that enables students to post a question directly and receive timely adaptive mentoring in the place and context where question encountered in reading e-book, and to use anchors to access discussions in a forum. And, a mentor recommender, based on the preference and knowledge level of the students, is provided to recommend appropriate capable peers to answer the issued questions. The experiment results showed that the discussions were increased significantly, and about 80% of students indicated that they benefited greatly by adaptive peer help.