冲压产品的协同设计是一个以知识为中心的活动。

Collaborative design of stamping product is an activity which takes knowledge as center.

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然后在以学习活动为中心的教学设计理论和PBL 的基础上，提出PBL网络课程的总体设计过程和主要设计内容。

Then we expound the gross designing course and main contents of PBL Web-based course based on PBL and instructional design centered on learning activity.

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