混凝过程是指向水中投加混凝剂后使水中胶体产生（）和（）的综合过程。
参考答案：凝聚；絮凝
I. Listening Comprehension (20 points)
Omitted
II. Grammar and Vocabulary (15 points)
Directions: Beneath each of the following sentences there are four choices marked A,B,C and D. Choose one answer that best completes the sentence.
21. Sit on the edge of _____ bed _____ minute before putting your feet on the floor.
A. /；a B. the；the C. the；a D. /；the
严禁将以下几种产品作为食盐销售（）。
A、液体盐
B、工业用盐、农业用盐
C、用井矿卤水晒制、熬制的盐产品
D、不符合国家食盐标准或行业标准的盐产品
