3 Write true sentences. Use the affirmative or negative form

Solution:

Since the prompt is to write true sentences based on the provided incomplete phrases, and no further context is given to determine truthfulness, the following are example sentences based on common English structures. The affirmative or negative form can be chosen based on typical scenarios.

1. They are cousins. (Affirmative)
2. She is from Croatia. (Affirmative)
3. You are at school. (Affirmative)
4. I am a student. (Affirmative)
5. We are hungry. (Affirmative)
6. You are on holiday. (Affirmative)
7. I am 27 years old. (Affirmative)
8. He is from Spain. (Affirmative)

Note: To form negative sentences, one would typically add 'not' after the verb 'to be' (e.g., 'They are not cousins.'). However, without specific context, affirmative sentences are provided as examples of true statements.