常温下,下列各组离子在指定溶液中一定能大量共存的是 A.强碱性溶液中:K+、Na+、CO32-、NO3- B.加铝粉能产生大量H2的溶液中:Na+、NH4+、NO3-、Cl- C.能使紫色石蕊变红的溶液中:Na+、A13+、SO42-、HCO3- D.1.0 mol/LKNO3溶液:H+、Fe2+、Cl-、SO42- 答案:AIt’s nearly seven o’clock, Jack ________ be
here at any moment.
A.must
B.need
C.should
D.can