波特认为每一个企业的设计、生产、营销、交货及对产品起辅助作用的各种活动都可以用（）表示。
参考答案：价值链
Simon _______ spend all his pocket money on clothes or snacks . but now he _______ saving some
of it . [ ]
A. was used to, is used to
B. is used to, used to
C. used to, is used to
D. used to, used to
教学中影响迁移的主要因素有哪些？
