Burning all the lights in the classroom will be a great______ on electric power.

Will you please also state your earliest delivery date, your terms of payment, and discounts for regular _______?

The manager spoke highly fo such ____ as loyalty,courage and truthfulness shown by his employees. 

 The need for an operation，especially an immediate operation， almost always comes as a ______ to the patient and his family. 

A U.N. peace-keeping _______ was sent to that country and the soldiers would devote all their _______ to their job.