（） provide the water to the pistons.

[单选题]A new water boiler was installed in our building last week, which could pro

[单选题]Aluminum pistons have （） coefficient of thermal expansion compared with those of cast iron.A . higherB . lowerC . the sameD . none of the above

[单选题]An advantage of aluminum pistons, when compared to cast iron pistons is （）.A . greater high temperature strengthB . better heat conductivityC . greater weight per cubic inchD . increased resistance to wear

[单选题]The pistons are cooled by oil supplied from the forced （） system.A . fresh waterB . sea waterC . lubricationD . fuel oil

[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]Due to （） action of pistons some relative motion between parts in contact in the coolant supply and return system must occur.A . reciprocatingB . rotatingC . runningD . removing

[单选题]D．ue to action of pistons some relative motion between parts in contact in the coolant supply and return system must occur.A．reciprocatingB．rotatingC．runningD．removing

[单选题]Pistons of marine medium speed diesel engines may be made of （） in order to keep the weight down for balancing purpose at high speed.A . leadB . forged steelC . alloy steelD . aluminum alloy

[单选题]（） pistons have low inertia and high coefficient of thermal expansion.A . Cast ironB . Cast steelC . Forged steelD . Aluminum

[单选题]The purpose of the program is to provide training for employees so that they can work ______.A． lateB． laterC． latelyD． latest