下面（）不是采购主要环节。
A.准备认证计划
B.评估认证需求
C.制定认证计划
D.采购人员绩效评估
参考答案：D
It was not until I came here ________ I realized this place was famous for not only its beauty but also
its weather. [ ]
A. who
B. that
C. where
D. before
请比较多基因决定的性状与数量性状的异同，并举例说明。如何分析这两种性状的基因
