In extreme weather conditions, either hot or cold, control of the air conditioning plant presents （） difficulties.

Each year in the United States, many black teenagers（）of school, either because they cannot keep up or they have to work to support their family.

When under maneouvring conditions with the machinery being manually operated the control unit or console should be （）

When under maneuvering conditions with the machinery being manually operated the control unit or console should be

With ducted air conditioning systems, the modern tendency is to use（）

It is reported that some scientists in the United States have found a new _____ for cancer.

The loss of the diesel engine cylinder air charge through leaky valves, piston rings, worn or scored liners, would be indicated by which of the following sets of conditions?（）

In extreme weather conditions, either hot or cold, control of the air conditioning plant presents （） difficulties.

For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes?（）

When installed for bilge pumping or ballast duty, centrifugal pumps require a （） to remove air from the suction pipe.

Banks have no liability for any delay or loss caused by postal or telex failure.

With techniques for running applications on most PC, you can ( ) a desktop icon or select the application from a menu.