You use energy every day. Energy is the ability (21) _______ change. When you ride a bike, you use energy from your body to make the bike move. Your parents use heat energy to change the food (22) _______ raw to cooked.
Not all energy is used as soon as you get it. Sometimes energy is (23) _______ to be used later, stored energy can be chemical energy stored in a battery or in your body. It can also be potential energy. Potential energy is based on (24) _______ position of the object. A soccer player standing ready to kick a ball has potential energy.
Energy of motion is also called kinetic energy. Potential energy converts, or changes into, kinetic energy when the thing or person begins to move. When the soccer player kicks the ball, kinetic energy is at work. Energy often changes forms. When you (25) _______ the light, electricity converts into light. When you eat, chemical energy from your food converts. into thermal and mechanical energy that allows you to move and work.
21.A. cause B. to cause C. causing. D. caused
22.A. from B. in C. with D. by
23.A. saved B. kept C. stored D. made
24.A. the B. a C. an D. x
25.A. switch off B. switch over C. switch back D. switch on
21.C. causing.
22.D. by.
23.C. stored.
24.A. the.
25.D. switch on.