You can understand any type of speech without difficulty. Whether the speech is live or on TV, you can understand all the words and phrases, even if they are spoken quickly. You can identify the accent of the speaker.
You can understand all forms of writing including manuals, news, complex instructions, and literary works. You can understand complicated articles about topics that you are not familiar with.
You can take part in any kind of discussion with mother tongue speakers fluently, using idiomatic expressions. You can express yourself naturally and use different shades of meaning in your speech.
You can write clear, flowing texts using an appropriate style. You can prepare detailed reports containing in-depth information. The structure of your texts is easy to follow and enables the reader to identify the most important points.
You can express yourself clearly and fluently and can do presentations and make speeches. You can adopt a style that is appropriate to the situation and the structure of your dialogue is logical and easy to follow.
You watch a TV program about English medieval literature which mentions texts related to the historical period: even if you don’t understand some specific words, you can understand the general meaning.
You’re at a conference in London: you communicate with your American and British colleagues without any difficulty, even making some jokes that contain idiomatic expressions.
You create an advertising text about the latest product released by your company: the text includes idiomatic expressions as well as colloquial phrases aimed at increasing sales.