目前较理想的抗氟剂是A.四硼酸钠 B.亚硒酸钠 C.硫酸镁 D.氢氧化铝 E.碳酸钙 发布时间:2017-06-22 12:47 │ 来源:www.tikuol.com 题型:单项选择题 问题: 目前较理想的抗氟剂是A.四硼酸钠B.亚硒酸钠C.硫酸镁D.氢氧化铝E.碳酸钙
题型:单项选择题 用所给单词的正确形式填空。1. The __________ (five) animal is a dragon. 2. Last year __________ (is) the year of the pig. 3. I'm __________ (clean) the living room. 4. Everyone __________ (put) on new clothes today. 5. I __________ (buy) a new pen yesterday. 查看答案