2,3,6,8,8,4,()
A.2 B.3 C.4 D.5
2,3,6,8,8,4,()A.2 B.3 C.4 D.5
2,3,6,8,8,4,() A.2 B.3 C.4 D.5
2,3,6,8,8,4,()() A.2 B.3 C.4 D.5
3,6,8,8,4,()A.2 B.3 C.4 D.5
正常食管内的pH值是A.2.5~4.0B.3.5~5.0C.4.5~6.0D.5.5~7.0E.6.5~8.0