Improve this sentence

Please improve the following sentence:

In fact, I have already completed classes with the same level in my high school in Hong Kong.
Basically, the grammar and the structure of your sentence are correct, but I think that will become better when you change into:
In fact, I have already completedl all the classes with the same level of my high school in Hong Kong.
Hope it helps you
圖片參考：http://hk.yimg.com/i/icon/16/3.gif

In fact, I have already completed classes of the same level at my Hong Kong high school.

In fact, the classes in high school what I have already completed have the same level in Hong Kong.

In fact, I have already completed classes with the same level in my high school in Hong Kong.

In fact, I have already completed many classes within the same level AT my high school back in Hong Kong.

* nothing much to change, you have a well written beginning, just a few words change and you are ready to go.

hope that helps.