I am a senior school student.

我是一名高中学生。

Triennium in senior school was very hard.

高中三年是艰苦的。

I gradually adapt to my new life in senior school.

我逐渐适应了高中的新生活。

I am a senior school student. Now, I am in grade two.

我是一名高中生，现在高二。

I am sure I will have a fruitful life in senior school.

我确信我的高中生活将会硕果累累。