(来学网)正常食管内的pH值是
  • A.
    (来学网)2.5~4.0
  • B.
    (来学网)3.5~5.0
  • C.
    (来学网)4.5~6.0
  • D.
    (来学网)5.5~7.0
  • E.
    (来学网)6.5~8.0