What time do you usually get up? And why?

Yesterday, I decided to start getting up at 4 a.m. every morning, because I feel it's necessary for me to do so. Until yesterday, I thought I could study at night, but I couldn't do so everyday, and I don't know (the reason) why. The book I read yesterday said humans can concentrate on something for only 3 or 4 hours in a day, and it's only in the morning. Therefore, I couldn't do anything after working, even if I really wanted to do it [or: even if I really tried]. That's why I'm trying to get up early and go to bed early as well. Recently, I felt like I may not have high motivation to study English, because I felt I didn't concentrate on studying [or: "I did not feel that I concentrated on studying"]. When I think about it now, it's natural, because I was tired after working every night. Truth be told, I'm not sure whether I can sustain these routines or not. However, I believe in myself and will do my best. And now, I feel that I am in such good condition [or: much better condition] to study English. Maybe, I'm a natural morning person, and I think I can do it. I feel a lot of things about myself are changing. For example, I'm trying to clean my room even though I hate cleaning. This is good opportunity to change myself. Thank you!

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