A good way to avoid repetition in writing, and at the same time to cement (= stick) sentences together so that ideas flow smoothly, is to use what’s called referencing and substitution (many examples of referencing and substitution in previous posts).
In this post we focus again on using it and this as substitutes for themes and rhemes. If you’re not sure what is meant by theme and rheme, please read this before trying the activity below.
('Z' = 'leave blank / zero article')
In IELTS, Referencing and substitution is mentioned in the Writing Task 1 public band descriptors and Writing Task 2 public band descriptors under the criterion Coherence and Cohesion, and in the Speaking public band descriptors under the criterion Fluency and Coherence.