题型:问答题 简答题 With more and more people__________ the importance of English, English training has become a profit-making industry.A.have realizedB.realizingC.to realizeD.having realized 查看答案
题型:问答题 简答题 0.05mol某两种烃的混和物在足量O2中完全充分燃烧,产物依次通过足量浓硫酸和碱石灰,增重分别为2.7g和5.5g。则此混和物可能为[ ]A.CH4 C4H10 B.C2H2 C4H10 C.C2H4 C4H10 D.C2H6 C3H6 查看答案