足球运动员用150N的作用力，将重4.5N的足球踢出，足球沿水平场地向前运动的最大距离为200m，则足球沿水平场地向前运动的过程中运动员对足球所做的功为(    )

①京广线     ②焦柳线     ③湘黔线     ④石长线     ⑤浙赣线．

小明的皮肤不慎被划破，结果流了很多血，小明感到非常疼，这说明皮肤中可能含有____ 组织、____ 组织和____  组织。

    Today is Sunday. My family likes to have fun together. In the morning, we plant potatoes on the farm. Then we go to the zoo to watch the animals. In the afternoon, we fly kites together. And in the evening, we go to the cinema to watch a film. At 8：00 pm, we watch TV at home.

 ____

 ____

 ____

 ____

 ____

-1$\frac{1}{2}$的倒数是____