1. She sang at the concert last year. (Past Simple for a completed action in the past).
2. Harry is the best student in my class. (Superlative adjective is used when comparing three or more items/people).
3. Bob wrote a poem last night. (Past Simple for an action completed in the past).
4. They didn't go to the theatre. (After 'didn't', the base form of the verb is used).
5. Liz is the prettiest girl in my school. (Superlative adjective is used when comparing three or more items/people).
6. Did the school team win the trophy? (After 'Did', the base form of the verb is used).
7. Ron is a very fast swimmer! (Adjective is used to describe the noun 'swimmer'. 'Fastest' is a superlative and would require comparison with others).
8. Clara is shyer than Sue. (Comparative adjective is used to compare two people).
9. I bought a ticket an hour ago. (Past Simple for an action completed in the past).
10. Julie met a famous person. (Past Simple for an action completed in the past).