Cast iron carrier rings, （） machined grooves, are provided for all the pistons.

[单选题]The cast iron（）for the cross-head are attached to the top section and seal off the crankcase.A . cylinder coverB . cross-head shoesC . guide-waysD . scavenging boxe

[单选题]The cast iron guide-ways for （） are attached to the top section and seal off the crankcase.A . the connecting rodB . the cross-headC . the piston rodD . the air box

[单选题]The piston rings are manufactured with a diameter （） the bore of the cylinder.A . larger thanB . smaller thanC . equal toD . none of the above

[单选题]Which is( )， iron or copper？A.heavierB.heavyC.more heavyD.much heavy

[单选题]The sealing rings are in four parts and pressed together around the piston rods by means of _____A．nutsB．boltsC．coil springsD．stuffing boxes

[单选题]The sealing rings are in four parts and pressed together around the piston rods by means of （）.A . nutsB . boltsC . coil springsD . stuffing boxe

[名词解释] CAST

[单选题]D．irections: In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation. Mark your answ

[单选题]The piston rings if found worn out （） and supplied by shipchandler.A . must replaceB . must to be equippedC . has to be repairedD . have to be renewed

[单选题]The film of oil between the rings and the liner is not only essential for the lubrication but also plays an important part in achieving （）.A . an oil sealB . removing heatC . a gas sealD . cooling the pisto