(来学网)唾液pH约在
  • A.
    (来学网)6.0~7.9
  • B.
    (来学网)5.0~6.9
  • C.
    (来学网)5.0~7.9
  • D.
    (来学网)6.0~8.9
  • E.
    (来学网)6.5~7.5