(来学网)天然水的pH一般为
  • A.
    (来学网)6.5~7.0
  • B.
    (来学网)7
  • C.
    (来学网)6.5~8.5
  • D.
    (来学网)7.2~8.5
  • E.
    (来学网)8.0~9.0