Directions: Last month you bought a pair of leather shoes from a shop. But now you find that the shoes are in bad quality. Write a letter to the manager of the shop to explain

1) your complain,

2) the problem with the shoes, and

3) your request.

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. You do not need to write the address. (10 points)

测定饮料中的咖啡因时，在样品干过滤时弃去前过滤液，对实验结果有影响。