题型:名词解释 选用浮选剂的基本原则是什么()。(1)适应性(2)安全性(3)经济性(4)可靠性(5)连续性A.(1)(2)(3)(4) B.(1)(2)(3)(5) C.(1)(2)(4)(5) D.(1)(2)(3)(4)(5) 查看答案
题型:名词解释 Many a student ____ wearing MP3 players while walking on the street.It’s quite dangerous.A.is used toB.are used toC.was used toD.were used to 查看答案