为什么过滤开始时,滤液常常有点浑浊,而过段时间后才变清?
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在做恒压过滤常数的测定实验的过程中,要把连着压力罐的尾阀稍微开一点,为什么?
当操作压强增加一倍,K值是否也增加一倍?要得到同样的过滤液,过滤时间是否缩短一半?
Listening Comprehension-Directions: Choose the best answer to complete each of the following sentences according to the information contained in the listening passage.Where did the woman see the three old men?
A. In front of her store.
B. In her front yard.
C. In her dream.
D. In her doorway.