Commodities shipped by air usually have high values per unit or are （）.

[单选题]Commodities shipped by air usually have high values per unit or are （）.A.co

[单选题]Where is the most air freight shipped in the passenger aircraft?（）A . separatelyB . Not clearC . In the lower partD . Not mention here

[单选题]The pressure of pilot air is usually （） than that of starting air.A . higherB . lowerC . lowD . high

[单选题]The pressurized air is usually cooled to increase the charge air （）.A . viscosityB . densityC . velocityD . electricity

[单选题]Air cocks, usually positioned at the （） in a circulating system, is used to get rid of the air in the system.A . bending jointB . expansion tankC . weldD . the highest point

[单选题]（） usually helps to induce air movement to assist combustion.A . Cylinder coverB . Main bearingC . The exhaust valveD . The piston movement

[单选题]A．ir cocks, usually positioned at the_______in a circulating system, is used to get rid of the air in the system.A．bending jointB．expansion tankC．weldD．the highest point

[单选题]The high air velocity leaving the compressor of an exhaust gas turbocharger is converted to pressure in the_______.A．inlet nozzle ringB．turbine wheel bladeC．diffuser passagesD．inlet volute

[单选题]The starting air system usually has （） to prevent starting if anything is not in order.A . stop valvesB . interlocksC . non-return valvesD . air vent

[多选题]Usually original air way bill separate for （ ）.A.consigneeB.shipperC.issuin