地下开采的煤层按倾角可以划分为近水平煤层、缓倾斜煤层、倾斜煤层、急倾斜煤层、其中缓倾 发布时间:2018-08-06 00:40 │ 来源:www.tikuol.com 题型:单项选择题 问题: 地下开采的煤层按倾角可以划分为近水平煤层、缓倾斜煤层、倾斜煤层、急倾斜煤层、其中缓倾斜煤层的倾角大小为()。A、25°~45°B、<5°C、>45°D、5°~25°
题型:单项选择题 ___total of 3,650 children were diagnosed as being sicken after drinking baby milk with ___chemical melamine.A The , B A , the C A , a D The , a 查看答案