二氧化钛(TiO2)中钛元素的化合价是( ) A.-4 B.-2 C.+4 D. 发布时间:2017-05-24 13:59 │ 来源:www.tikuol.com 题型:选择题 问题: 二氧化钛(TiO2)中钛元素的化合价是( )A.-4B.-2C.+4D.+2
题型:选择题 — What time do you usually have your first class? — ______ eight o'clock ______ the morning.[ ]A. At, onB. At, in C. On, in 查看答案