皮皮学，免费搜题
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搜题
【单选题】
在物镜上滴松柏油的作用是( )。A.
增大物镜上的孔径
B.
聚集更多的光线，提高鉴别能力
C.
润滑
D.
清洁
拍照语音搜题，微信中搜索"皮皮学"使用
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知识点：
皮皮学刷刷变学霸
举一反三
【简答题】2.
Which of the following is not included in the fuel injection system?A. air induction system B. fuel delivery system C. waste gas emission D. electronic control system
【单选题】The direct acting mechanical governor used with some small diesel engines, controls fuel flow to the engine by（）
A.
governor flyweight action on a pilot valve which controls fuel injection
B.
governor flyweight motion acting on fuel controls through suitable linkage
C.
positioning a butterfly valve in the fuel delivery system positioning
D.
a servomotor piston attached to the fuel controls
【单选题】Movement of the pump control rack in a fuel injection system using individual plunger-type pumps
A.
changes the position of the fuel inlet ports
B.
changes the length of the pump stroke
C.
varies the quantity of fuel delivered
D.
varies the compression of the delivery valve spring
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