为了除去硫酸铜溶液中含有的Fe²⁺杂质，先加入合适的氧化剂使Fe²⁺氧化为Fe³⁺，下列物质中最好选用 [ ]

A．H₂O₂溶液

B．KMnO₄溶液

C．Cl₂水

D．HNO₃溶液

You____Tom at the party yesterday;he went abroad for a holiday last week.

A．should have seen

B．might have seen

C．mustn’t have seen

D．couldn’t have seen