B. 请根据句意从方框中选择合适的词，并用其适当形式填空，使句子通顺。

    We all need exercise. Exercise uses up food that we eat and keeps the body full {#blank#}1{#/blank#} energy(能量). Exercise makes your heart and muscles(肌肉) strong. Exercise {#blank#}2{#/blank#} makes you feel relaxed. If you exercise several times a week, you will stay happy and {#blank#}3{#/blank#}. There are many {#blank#}4{#/blank#} to exercise. You can walk, run or swim.

    However, most people cannot do this. It is too far from their homes to their offices. They have no choice {#blank#}5{#/blank#} to drive to work. First, these people don't have a chance to exercise because they are sitting in their cars for two to four hours each day. Second,  driving is challenging(具有挑战性的), {#blank#}6{#/blank#}in rush hours, and needs too much attention.  It makes a person tired out. When these people arrive home after work, they don't want to take exercise.

    Some western countries, such as the United States, have problems with {#blank#}7{#/blank#}. Many people don't have enough exercise. They have to work from morning till night, so they don't have time {#blank#}8{#/blank#} exercise.

    Today, many people in the West are fat, which causes health problems. Doctors say exercise can help people both lose {#blank#}9{#/blank#} and improve their health. So many people are trying to get more exercise. But it takes time to change, and when people don't see a {#blank#}10{#/blank#} right away, they will lose heart and stop exercising.