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。
2
The learning curve for using new pointcuts is pay as you go.
使用新切入点的学习曲线是随用随学。
3
For same aim, when you take something or push-and-pull, you should pay attention to curve both knees.