血液经体循环后，发生的变化是（  ）

根据短文内容，选择正确答案。

Long long ago, there was a spider. She found a beautiful farm. She liked the farm and decided to live there forever.

    One day, the spider caught a little bug. When the spider ate it, the bug said, “If you let me go, I will tell you an important thing. The thing will save your life.” The spider stopped and listened.

    The little bug said, “You'd better get out of the farm. The harvest is coming! If you stay here, you will be killed by the farmer's machine.”

    But the spider didn't listen to the bug and ate it for lunch. The next day when she was sleeping, the farmer came to have a harvest. The spider was killed by the machine.

由直线y=x+2上的一点向圆${\left(x-3\right)}^2+{\left(y+1\right)}^2=2$引切线，则切线长的最小值（    ）

按课文《春雨的色彩》内容填空。  

① 春雨，像春姑娘纺出的____，轻轻地落到地上。

②课文里____、____和____在争论春雨的颜色。