Dear Qang Ping,
Thanks for your email.Now let me tell you my view on the matter.
First of all,I have to say,you need to understand how your parents feel.They expect nothing from you expect good academic grades,since they are concerned about your future.However,it's probably not right of them to prevent you for taking a part-time job during the winter holiday.
Firstly,you can get a lot from the social practice.You'll earn more than money .Secondly,you shoulden't study all day to become a book worm.You need to combine your study with practice .Lastbut not least,the experience you get from the job will have a very positive influence on your future.
In a word,you should stick to your point of view and try to persuade your parents.
Best regards,
Li Hua