题目

__________ from heart trouble for years Mr. White has to take some medicine with him wherever he goes.      A. Suffered      B. Suffering    C. Having suffered       D. Being suffered 答案：C 解析: 略下列化学用语正确的是 A． HCO3－+H2O＝CO32－+H3O＋ B．NaCl(S)＝Na＋ (aq)＋ Cl－(aq)C． S2－ +H2O H2S+ 2OH－ D．SiO32－ +H2OH2SiO3+2OH－