— Thomas didn't come to school for the meeting, did he?

—  No. He ____. The meeting had been cancelled.[ ]

A. shouldn't have come

B. should not come

C. didn't need to come

D. wouldn't have come

下列过程中,没有明显实验现象的是(　　)

A．向Fe(NO₃)₂溶液中滴加稀硫酸

B．将HCl通入NaAlO₂溶液中

C．加热溶有SO₂的品红溶液

D．向碳酸氢钠溶液中滴加氢氧化钠溶液