Both of my parents insist ______ a computer for me, but I don’t think it is necessary.

A．to buy

B．on buying

C．buying

D．in buying

下列各实验装置图的叙述中，正确的是（　　）

A．装置①为放出萃取溴水后的苯层

B．装置②为喷泉实验

C．装置③可用来吸收HCl气体

D．以NH₄Cl为原料，装置④可用于制备少量NH₃