The feed proximate analysis method can measure the（ ）content in the feed. A: Calcium B: Phosphorus C: Crude protein D: Crude fat E: Neutral detergent fiber

If the detergent type lubricating oil being used in a diesel engine is black, the oil （） A: must be centrifuged B: must by filtered C: must be changed D: is holding finely dispersed carbon in suspensio

What istrue of washing trains? A: Chemical washes are used daily. B: Washing occurs in the inspection shed. C: Detergent must be used with each wash. D: The washing machine recollects and reuses water.