Restricted use is a stage where learners do controlled practice of the target language. Restricted use is part of the model Authentic Use, Restricted Use and Clarification and Focus (ARC).

Example
Learners have seen examples of the structure 'If I were you…' in a text from a teenage magazine. They then look at the form and practise making it using prompts.

In the classroom :
The ARC model is useful to label the different stages of a lesson. For example, a lesson following a model CRCAC would have a presentation stage, practice, clarification, free practice and further clarification based on problems that arise in the free practice.

Further links:
https://www.teachingenglish.org.uk/article/planning-a-grammar-lesson
https://www.teachingenglish.org.uk/article/lesson-plans
https://www.teachingenglish.org.uk/article/speaking-elementary-learners
https://www.teachingenglish.org.uk/article/drilling-1
https://www.teachingenglish.org.uk/article/teaching-speaking-unit-5-techniques