You have worked in a Non-Governmental Organization for several years, but now you need to quit the job because you are moving to another city with your family. Write a letter to your boss Mr. Smith to tell him your decision and the reason, and your appreciation for the work experience in this agency. You should write about 100 words on ANSWER SHEET 2. Do not sign your own name at the end of the letter. Use 'Li Ming' instead. Do not write the address.