—How long ________they_________?—Sorry, I don't know. But I know that Mr. Chen is going to _______a nurse next month.
A:did, get marry; marry with
B:have; got married; marry
C:have; been married; marry
有一无色溶液,其中滴加数滴氯化钡溶液,发现有白色沉淀产生,此沉淀不溶于稀HNO3,则该溶液中大量存在的离子是( )