根据短文内容，从下面选择适当的选项补全短文，选项中有一项为多余选项。
From English words to history events, you have to remember a lot at school. Is it difficult? Do you want to find some good ways to remember easily and quickly? If you have a photographic memory (过目不忘的记忆), will things be different? Scientists have made an effort to find ways to improve our memories for years.
Sleeping in a rocking bed
When we were babies, we could easily fall asleep in our mothers' swaying (摇晃的) arms. Some scientists have found that if we sleep in a bed which moves softly forwards and backwards, we can have a deeper sleep. Buying a rocking bed may be a good idea and it must be very fun. Haha!
Becoming emotional
Thinking back to the past, it seems that we could always remember those things that make us sad or happy easily. Why? The moment you become emotional, you can remember things really well. Because the amygdala (杏仁核) in our brain is responsible for dealing with both emotions and memories. The brain wants us to remember those things. When you want to remember some knowledge next time, try to make yourself angry or excited. Then, take out your book to catch the chance to learn new things.
In an experiment (实验), scientists divided 100 people into two groups. People in the first group were asked to ride a bike slowly for 60 minutes. People in the second group only had to do it really fast for 6 minutes. It shows that the short but intense (剧烈的) exercise made the brain produce more of a chemical called "brain-derived neurotrophic factor (脑源性神经营养因子). People can remember things quickly with this chemical. That's the time when you need to sit down and start to remember things.
A. Having intense exercise
B. Because memories can influence emotions (情绪).
C. Here are some tips from their findings.
D. Its amount (数量) goes to the highest point after six minutes of intense exercise.
E. It can improve our memories as well.
F. Because emotions can influence memories.
