给装有下列少量固体物质的试管加热，试管底部物质不可能完全消失的是[ ]

A．NH₄HCO₃

B．NaHCO₃

C．NH₄Cl

D．(NH₄)₂CO₃

With computer users linker to the internet growing （） every year,business is trying to cash in on the worldwide network.

A．at million

B．with a million

C．with one million

D．by million