木脂素
参考答案：木脂素为具有苯丙烷骨架的两个结构中通过其β，β’碳相连而成的一类天然产物。
Thanks to the Party’s opening and reform policy, people in China are _____ than they were thirty years ago .
A．worse off
B．much better off
C．more better off
D．quite better off
对产品的可得性最准确韵绩效衡量指标是：（）
A.缺货频率
B.顾客频率
C.运作绩效
D.发出订货的完成状况
