单项选择题
When a clarifier is running the impurities and water collect at the bowl （）.
A.center B.periphery C.inlet D.upper parts
单项选择题 A centrifuge arranged to separate impurities and small amounts of water from oil is known as （）.
单项选择题 A centrifuge arranged to separate two liquids is known as （）.
单项选择题 Emulsification of oil will occur when mixed with （）.
