Consider this typical C1 PDF prompt:

$$t = \infty$$

The meeting had to be called off on account of the inclement weather. 4. Precision with Connectors and Conditionals

Most B2 learners can paraphrase a sentence by changing one or two words. C1 rephrasing, however, often requires you to restructure the entire clause. You are not just avoiding repetition; you are demonstrating control over nuanced grammatical structures.