按题目要求作图

①利用图中的定滑轮和动滑轮绕制滑轮组，要求既要最省力又要能够改变用力的方向．

②如图所示，试在甲、乙两个“ ”内选填“电压表”和“电流表”的符号，使两灯组成并联电路。

③请在图中补画一根导线，使得滑动变阻器的滑片向右移灯泡变暗.

    BEIJING---No Car Day was first started by 34 cities in France on September22, 1998. It was started to protect the environment. By now, more than 1,000 cities around the world have had a No Car Day.
    The first No Car Day in China was in Chengdu in 2001. Other cities, including Taipei, Shanghai and Wuhan, also support( 支持) the day.
In Beijing, more and more people are joining in the activity. It asks drivers to leave their cars at home for one day each month and walk or ride a bike to work. It also calls on Beijingers not to use cars on June 5 ( World Environment Day ).The slogan for the day is, “ If we drive for one less day, we can have one more nice day.”
    So far more than 200,000 drivers have shown their support “ We can't control the weather, but we can choose not to drive,” said Wu Zonghua, a car club chairman. Beijing is trying to have 238 blue sky days this year. In the first quarter of this year, Beijing only had 52 blue sky days. This was 11 days less than the number for the same period last year. Much of the dust（ 灰尘 ） comes from the desert（沙漠）, but cars cause most of the air pollution.（污染）. We must do more for No Car Day.

解释下列词语

①喝彩

②姿态