Fill in the blanks in the sentences using the words provided.

Solution:

The task is to complete the sentences using appropriate prepositions. Let's analyze each sentence and choose the correct preposition from the options provided in the text: 'in', 'on', 'by'.

1. We had a fantastic holiday. We stayed on the north coast of Spain. We camped in the mornings, we swam by the sea and mum and dad sunbathed on the beach. On hot days we spent our time in the mountains.
2. We had a fantastic holiday. We stayed on the north coast of Spain. We camped in a field.
3. We had a fantastic holiday. We stayed on the north coast of Spain. We camped in a field. In the mornings, we swam by the sea and mum and dad sunbathed on the beach. On hot days we spent our time in the mountains. We stayed by a small river.
4. In the mornings, we swam by the sea and mum and dad sunbathed on the beach.
5. In the mornings, we swam by the sea and mum and dad sunbathed on the beach. On hot days we spent our time in the mountains.
6. On hot days we spent our time in the mountains.

Answer: 1. on, 2. in, 3. by, 4. by, 5. on, 6. in.