It is sometimes difficult to distinguish between the element of envy itself and the defences against it.

有时候很难区分哪些是嫉羡的防御，哪些是嫉羡本身。

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However, this is not always the case, and it is sometimes difficult to distinguish between subsystems and localities.

然而这并不是一成不变的，而且有时也很难区分出子系统和位置。

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Sometimes it is difficult to distinguish between application and business logic and connectivity and integration logic.

有时很难在应用程序和业务逻辑与连接和集成逻辑之间进行区分。

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Tension headaches can sometimes be difficult to distinguish from migraines, but unlike some forms of migraine, tension headache usually isn't associated with visual disturbances (blind spots or flashing lights), nausea, vomiting, abdominal pain, weakness or numbness on one side of the body, or slurred speech.

CNN: Tension headache