糖的检识
参考答案：
主要是利用糖的还原性和糖的脱水反应所产生的颜色变化、沉淀生成等现象来进行理化检识，利用纸色谱和薄层色谱进行色谱检识。
Mr. Smith is _____ great fun and we had _____ great fun with him.
A．a; 不填
B．a; a
C．不填; a
D．不填; 不填
The Australian boy has a good __________ of Chinese and can express himself freely in it.
A．demand
B．power
C．command
D．usage
