阅读下面短文，根据首字母提示，完成所缺单词，使短文通顺，意思完整，语法正确，一空一词，

并将答案依次填写在题后相应的横线上。

     I used to be an unhappy girl. I had (1)f_______  friends around me. I wanted to make friends with others,

but I didn't know what to do. I felt lonely. To change my life, I had to (2)1_______ how to get along with

others. What did I do? I said hello to my classmates actively when I (3)m_______ them. I invited them to my

home on weekends. And I offered them my (4)h_______ when they had some difficulties in their studies. I felt

happy when I was with them. There is no happiness without friends. (5)N_______ I have many friends. I've

become a happy girl at last.

用于干燥环境中的混凝土，应优先选用（）水泥

A.矿渣

B.火山灰

C.粉煤灰

D.普通