A．llowances may be made for the expansion and contraction in piping by the use of expansion joints or ().

A．Unions

B．Retractable flanges

C．Union bulkhead fittings

D．Bends or loops in the line

[单选题]Pistons may be made in （） in order to keep the weight down for balancing purposes at high speed.A . cast ironB . forged steelC . stainless steelD . aluminum alloy

[单选题]The business cycle is made up of many phases and one of them is the expansi

[单选题]The business cycle is made up of many phases and one of them is the expansi

[单选题]The business cycle is made up of many phases and one of them is the expansi

[单选题]The business cycle is made up of many phases and one of them is the expansi

[单选题]Government is not made in virtue of natural rights, which may and do exist

[单选题]Government is not made in virtue of natural rights, which may and do exist

[单选题]Government is not made in virtue of natural rights, which may and do exist

[单选题]Government is not made in virtue of natural rights, which may and do exist

[单选题]Government is not made in virtue of natural rights, which may and do exist