For unadjustable ones, the exit may be the best choice.This paper also studied the relevant barrier, ways and policies.The last part can be viewed as a case discussion.

• 而对不可调整升级型衰退产业本文则做出了退出的建议，并对退出的障碍、退出的方式及顺利退出的政策保障进行了论述。