我會努力學習, 唔會令你失望..英文點講啊.. ?

I'll keep with the good work and won't let you down.

或者

I'll keep up the good work and won't disappoint you.

2007-12-24 15:32:40 補充：
sorry, 打錯左添! 應該是﹕ I'll keep up the good work and won't let you down才對。

i'll study hard and won't let you down.

I will study hard and not disappointed you.

I will work hard on study and won't disappoint you.

i will do my best, and will not disappoint you.