His sister left home in 1998, and _______since.

A．had not been heard of

B．has not been heard of

C．had not heard of

D．has not heard of

小儿腹泻重度脱水纠正后，可出现哪些电解质紊乱（）

A.低钾血症

B.低钠血症

C.低钙血症

D.低镁血症

E.低氯血症