In this exercise we need to fill in the blanks with the correct choices. So, let's separate each sentence as follows:
1. The right answer is un incendio
<em>Hay </em><em>un incendio</em>
whose meaning is:
<em>There is </em><em>a fire</em>
So, there is a fire in some place. The context of the story does not specify whether the fire has been provoked by someone or it arose spontaneously
2. The right answer is se desconocen
<em>Las causas de lo que ha ocurrido </em><em>se desconocen</em>
whose meaning is:
<em>The causes of what has happened </em><em>are unknown</em>
As we said, the fire could be provoked by a pyromaniac or simply it's because of the mother nature.
3. The right answer is mucha sequía
En los últimos meses, ha habido mucha sequía
whose meaning is:
<em>In recent months, there has been </em><em>a lot of drought</em>
This is maybe the cause of the fire. There is a lot of drought that probably causes the great fire.
4. The right answer is el incendio se extienda
<em>Las autoridades temen que </em><em>el incendio se extienda</em>
whose meaning is:
<em>Authorities fear that </em><em>the fire is spreading</em>
It is possible that the fire is spreading if the firefighters couldn't control it. So, it is possible that they would need several firefighter trucks
5. The right answer is están en peligro
<em>Los pueblos de los alrededores </em><em>están en peligro</em>
whose meaning is:
<em>The surrounding villages </em><em>are in danger</em>
People are in danger if the fire is no stopped. So, the authorities must stop the fire as soon as possible.