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You will start with a review about adjectives.
Adjectives Review
Exercise 1, Exercise 2, Exercise 3, Exercise 4, Exercise 5, Exercise 6, Exercise 7.
Now There are some grammar explanations about Comparative and Superlative form of adjectives.
Explanation 1, Explanation 2
And there are some exercises about comparative adjectives and superlative adjetives.
Exercise 1, Exercise 2, Exercise 3, Exercise 4, Exercise 5, Exercise 6, Exercise 7, Exercise 8, Exercise 9.