The scavenging air ports are located at （） that they are just exposed by the upper edge of the piston when the piston is in the bottom dead center position.

[单选题]On top of scavenging air box is mounted a strong cast iron frame for each cylinder known as（）A . cooling jacketB . cylinder linerC . piston crownD . cylinder cover

[单选题]The ports are drilled in the liners at an angle of approx 20℃ the result being that （） is given a rotary movement.A . the scavenging airB . the exhaust gasesC . the mixed airD . the spray oil

[单选题]The street garden is located in _________used to be a market placeA．whichB．whereC．whoD．what

[单选题]Scavenging is （） of exhaust gases by blowing in fresh air.A . the suctionB . the compressionC . the removalD . the deliver

[单选题]Cross scavenging requires the fitting of （） to prevent air or exhaust gas escape when the piston is at the top of the stroke.A . a exhaust valveB . a piston skirtC . a piston crownD . an air suction valve

[单选题]Clearance volume scavenging in a turbocharged, four-stroke/cycle diesel engine is accomplished （）.A . during the valve overlap periodB . with only the exhaust valve openC . at a pressure below atmosphericD . without cooling the cylinders or pisto

[单选题]Piston cooling fins are locatedA．atop the piston crownB．beneath the piston crownC．at the base of the piston skirtD．inside the cylinder liner cooling water jacket

[单选题]The water pockets located on the underside of inflatable liferafts（）.A . stow rainwater; these 4 spaces do not take up valuable spaceB . act as stabilizers by filling with sea water as soon as the raft is inflated and uprightC . hold the freshwater r

[单选题]The condensers located in various stages of a flash evaporator are cooled by( ).A．distillateB．seawaterC．brineD．air

[单选题]The author mentions the ports of Los Angeles and Long Beach to ______.［A］prove they are the largest ports in the United States［B］demonstrate they create many new job opportunities［C］highlight that shipping is less glamorous than making movies［D］empha