What can you do at levels B2 and C1?
At level B2, you can express yourself clearly and explicitly and discuss and negotiate successfully. You have a large command of the vocabulary needed for your field of specialisation and for most general topics. Your usage of grammar is sound.
At level C1, you can express yourself spontaneously and fluently. You are familiar with idiomatic phrases and can vary your style of language as appropriate. You can use the language with a high degree of grammatical accuracy.