The disadvantages are that you have to pay for them, they have a steep learning curve, and they don't allow you access to their source code in case you need to modify a feature.

而缺点是您需要为它们付费，有一段陡峭的学习曲线，而且当您需要修改功能时不允许您访问源代码。

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Even, its control system commonly consists of simulation instrument, can't modify the changing surge curve of compressor in time and can't control nonlinear surge curve preferably.

且控制系统一般采用模拟仪表构成，在压缩机的喘振线发生变化时不能及时修正，对非线性的喘振线不能较好的实施控制。

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This line, called a cotangent line, is used by the system to modify the curve.

这条线叫做共切线，是系统用来改变曲线形状的。

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Early days and the adage that a rising tide lifts all boats is one that will be bandied about, but it seems we have already passed the discover-and-duplicate phases of the growth curve and are firmly in rethink and modify when it comes to daily deals.

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