Ms. Zhou Mr. Li is humorous. They are popular among us students.
A:Both; and
B:Neither; nor
C:Either; or
D:Not only; but also
当钟乳石和石笋相接到一起时,便形成完整的( )。
用下列方法除去含Ca2+、Mg2+、HCO3-、Cl-的硬水,所得水含离子浓度最小的是( )