如图，观察图形填空；包围着体的是____；面与面相交的地方形成____ ；线与线相交的地方是____.

下面四个图形中，∠1与∠2是对顶角的图形（      ）.

完形填空

    Look at this girl.  1 name is Wang Meimei.  2 is twelve. Wang Ming is her brother. He is3 Class Three，Grade Two. Do you know how old he is? He is fourteen years old. The brother4 sister are in No. 2 Middle School. Their mother5 a teacher. She is an6 teacher. Their father, Mr Wang, is a teacher, 7. He is a Chinese teacher in No. 8 Middle School. Their students all love them because they love their students. They have(有) a cat.8 name is Mimi. 9 a nice cat. The cat and Wang Meimei are 10friends.

所有经线的形状特征是____ ，并且经线的长度特征是____ ，经线指示____ 方向。

有下列四种微粒：① ${}_8^{18}$ O、② ${}_{12}^{24}$ Mg、③²³₁₁Na、④ ${}_7^{14}$ N，