If over a period of time, the oi1 film partially disappears, so that dry areas are formed

A diesel engine burns _____ a gasoline engine of the same capacity in the same period of time.

The trouble－free life of an engine indicates _____.A.the period of time during which no tr

The periods of light and darkness the moon created were the first accepted periods of time

The cooling water temperature should be gradually reduced over a period of （),and then sh

What is the main idea of this passage？A．The Ice Age was a long period of time.B．Great glac

Her time at the university was the most ________ period of her life.A eventfulB fancifu