X、Y、Z是3种短周期元素，其中X、Y位于同一主族，Y、Z处于同一周期．X原子的最外层电子数是其电子层数的3倍．Z原子的核外电子数比Y原子少1．下列说法正确的是（　　）

根据短文内容判断正误，符合短文内容的写正确，不符合的写错误。

A Letter(—封信）

Dear Lucy,                                                                                                                                               Oct. 25

  How are you? I miss you so much. We have a new house now. It's near our school. I can go to school quickly. There is a library near our house. There are a lot of trees and flowers around(围绕)my house.

  Please come and visit us. If (如果) you get to the train station of our town, you can walk straight to the post office. Then turn left. My house is between the school and the park. I will welcome you warmly(热烈地).We can play together.

                                                                                                                                                                       Ann