Answer:
We must complete the blanks in the sentences.
1) Elena y silvia ___ muy bien anoche.
Where the word is (vestirse). Now, you can notice that the verbal person here will be "ellas" because are both feminine names, and the person talkin is not in the group, so the correct conjugation would be "Ellas se vistieron..."
Elena y Silvia se vistieron muy bien anoche.
2) Ayer, nosotros __ a un restaurante.
Here the verbal person is "nosotros" and the verb is "ir", the sentence starts with "ayer" that means "yesterday" so we must use the preterite tense, the correct conjugation is:
Nosotros fuimos..
"ayer, nosotros fuimos a un restaurante.