题目

下列说法正确的是（ ） A . 工业制水泥、玻璃都要用到石灰石；制水泥、陶瓷都要用到黏土 B . 刚玉、金刚砂，红宝石、蓝宝石的主要成分是氧化铝 C . 石英、硅石、水晶、珍珠、玛瑙主要成分都是SiO2 D . 氮化硅陶瓷，光导纤维，石英玻璃都属于新型无机非金属材料 答案：A假定你是李华，最近你的美国网友James来信和你讨论“网络不文明用语”的话题。请你就此给他写封回信，内容要点如下：1.简要概括其现状及危害；2.给出可行的建议。注意：1.词数：100左右；2.信的开头和结尾已经给出，不计入总词数。3.开头语已为你写好，不计入总词数。Dear James,How are you going? I miss you very much. I’m writing to you to talk about the uncivilized words used on Internet. __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Yours,Li Hua