This can be interpreted in several ways, depending on what happens and who appears in the dream. If it is the dreamer who calls, it represents the need for external support at that time. Hearing a call and not paying attention, or being able to answer, alludes to a feeling of guilt about a lazy or careless attitude. To answer the call, however, indicates willingness to offer help to the people around you. On the other hand, it may be a matter of your unconscious trying to get your attention. Something important may be happening without you being aware of it. If you dream that someone knocks at the door, soon fortune will smile on you.
Improving memory can be done in a number of ways, and one of those is by having a good night's sleep. During sleep, your mind is still busy and going through the process of consolidation, where it strengthen your memories as well as the "practice" skills, which you have learned while you're awake. According to the associate professor at NYU Langone Medical Center, Dr. Rapoport says that something happens while we are all sleeping, and it helps us learn things better. Thus, if you're trying something new, you can perform it better right after you sleep.
Dreams reflect our actions that we have already performed. Most of us have dreams activities relating to our past life. One of the common dreams that every individual has gone through is their experiences during the school life, where you would get images of teacher hitting you, making you feel numb and shameful.