For this part, you are allowed thirty minutes to write a letter. Suppose you are Li Ming, write Professor Wang, your former teacher, ask him to write you a letter of recommendation. You should write at least 150 words according to the suggestions given below in Chinese. 1.告诉他你是谁。 2.你请求他做什么以及原因。 3.表示感谢。

参照国家《工业企业设计卫生标准》的规定，食品企业应位于（）。

A.居民区常年主导风向的下风向和水源的下游

B.居民区常年主导风向的下风向和水源的上游

C.居民区常年主导风向的上风向和水源的下游

D.居民区常年主导风向的上风向和水源的上游

E.以上都不对