I climbed mountains with my friends last Sunday. It was very hot. When we climbed halfway up the mountain, we were very hungry and thirsty. We decided to have a rest. My friends bought some water and fruit. I brought some bread and milk. We were very happy. Finally, we were on the top of the mountain. But my hat was flew away. I was sad

    It was a happy and sad day.

如图，在平面直角坐标系xOy中，⊙P与y轴相切于点C，⊙P的半径是4，直线y=x被⊙P截得的弦AB的长为4$\sqrt{3}$，求点P的坐标．

下列各组离子能在水溶液中大量共存的是

空气中氧气含量测定的再认识．

【查阅资料】

比一比，组词。

维____        孤____      浩____      陵____

唯____        狐____      皓____      凌____