1. I am good at maths. 2. He doesn't well in Chinese./He is bad in Chinese. 3. I am a middle school student. 4. I'm in xx middle school grade XX class XX.
1. I am good at math. 2.He is not good at Chinese.(be good at…是固定短语,表示擅长…) 3.I am a middle- school student. 4.I study in…middle school and I am in class…,grade …
I am good at math.或者I do well in math. He is not good at chinese.或者He does not well in chinese. I am a middle school student. I am in class +,grade+of+middle schools'student.