北半球各地白昼最长的一天是

将3Ω和5Ω的两个电阻串联接在9V的电源上，它们的总电阻为____ Ω，电路中的电流为____ A．

如图所示，图中有5组数据（用字母代表），现准备去掉其中一组，使剩下的4组数据的线性相关性最高，那么应该去掉的一组是（　　）

短文改错。

    One summer evening, I was playing and ____ some childs ____ by a river. We saw a lot of frogs(青蛙) in the water. One of us said, “Let's to see ____ who can Catch most ____ frogs.” Then we began. After while____  we caught a lot. We are ____ having a good time when a farmer shouted at us. “Don't caught ____ frogs!” Then he told us how importance ____ they are to farming. They eat a lot of bad insects(害虫) every year, Caught ____ frogs must be stopped. After hear ____ that, we felt very sorry.