When I was a middle school student, I studied at a small school in a town. I always easily ranked among the top three in my class, perhaps due to the school's simple curriculum, or the lack of tough competition. But once I entered the city's best high school, things changed. I needed to study ten subjects at the same time and most of my classmates were very smart. I didn't realize how difficult circumstances would be. I felt, too, like I was drowning in sadness, having been separated from old friends. When eventually I got a very bad grade, it served as a wake-up call: I realized that a lot had changed, and I that I, too, would have to adapt. I needed to improve my grades, and so I immediately set some goals and made a plan. I studied hard and worked to find a new learning method which would better suit me. What's more, I got to know my classmates during our leisure time, in an effort to make new friends. All of this proved very effective. When I graduated from high school, I had achieved the second highest grade in my class, and had made a lot of friends. In our lives, we will encounter a variety of changes and challenges, and the best way to meet with them is always by endeavoring to improve ourselves.

Your composition was very good! I have made mostly stylistic & word choice changes, to make it sound a bit more "native". Keep up the good work!

你写的非常好！大多数的变化只是我自己喜好的风格变体，一点儿更地道的。真不错吧！加油！