在实验中,有两次DNA的沉淀析出,其依据的原理是( ) ①DNA在氯化钠的物质的量浓度为0.14mol/L时溶解度最低 ②DNA在冷却的体积分数为95%的酒精中能沉淀析出 A.两次都是① B.两次都是② C.第一次是①,第二次是② D.第一次是②,第二次是①We have two rooms to live in, but I can't decide_________. A.to choose which oneB.choose which oneC.which one to chooseD.which one will I choose