果法变色与下列（）项无关。
A.酶促变化
B.美拉德反应
C.pH变化
D.冷藏
参考答案：D
The mountain is so high that its top snow all the year round.
A．is covered with
B．is filled with
C．is made of
D．is used by
森林的年龄是森林( )指标。
A．稳态的B．年龄结构的C．密度的D．发育的
