UNIT (1 )
The Wheel
I. (a) Read the passage
Wheels are used today for many purposes besides carTYing things. On some buildings, and in many pubfic places, you Giill find a flag-staff. At the top of the flag-staff there is a small wheel, and• over it passes a loop of a rope. one end of which is down near the ground. When we want to fly the flag, it is tied to the loop. the rope is pulled, and the flag goes up. The end of the loop is tied. to the lower end of the.flag. A wheel of this kind, over which a rope passes. has a groove so that the rope cannot slip off. Such a wheel is called a pulley wheel or a pulley.
Its purpose is simply to change the direction of avull. To raise a flag to the top of a flag - staff, it is more convenient to be Åble to pull the rope down, than / it would be to climb_the staff and pull the flag up. The pulley does not make the effort any less, and in this case thgy_e is no need to do so because the flag is not heavy. But the pulley is convenient.
(A) correct word or words to complete each sentence; wheels were used for
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