The ratio of the work done by the machine _________ the work done on it is called the efficiency of the machine.

Never attempt to machine a work-piece without first checking the operation of the machine.( )

The ratio of the work done by the machine ______ the work done on it is called efficiency of the machine. A: against B: to C: with D: for

中国大学MOOC: We plan to _________ this machine when funds become available sometime in 2015 with an upgraded machine.

We plan to _________ this machine when funds become available sometime in 2015 with an upgraded machine. A: risk B: undertake C: violate D: replace

The ratio of the work ______ by the machine to the work _____ on it is called the efficiency of the machine. A: to do ...to do B: doing....doing C: having done ... having done D: done ...done

When self check-in, you can get your boarding pass and your bag tag from a machine. What is the machine called? A: Bag tag. B: Kiosk. C: Boarding pass. D: Customs.

There was an ( __ ) (engineer) problem of the machine.

The computer is an useful machine.

what is Jane learning to use（） A: A television set. B: A washing machine. C: A pulic telephone. D: A candy machine.