“学然后知不足,教然后知困”这句话反映了师生关系的什么特点 ( )
A.尊师爱生
B.民主平等
C.教学相长
D.辨证统一
参考答案:C
As we all know, the number of Tibetan antelopes(藏羚羊) ________ becoming ___________.
A.is; less and less
B.are; less and less
C.is; smaller and smaller
D.are; smaller and smaller
分离黄酮类化合物宜选用
A.氧化铝吸附色谱B.聚酰胺色谱C.分配色谱D.pH梯度萃取法E.以上都不可