Question

Fill the blank with the preterite tense of the verb in parentheses.

Answer 1

Remember that it is 
-é           | amos
-aste      | asteis
- ó          | aron

Julia Y marcos are They which is 
- I                                  | We
- You                             |
- He/She/ you formal  | They / They girls (plural) They

Miraron (I believe)
Why i say this is because it says "they watched tv last night" (answer to 1.)

Answer 2

The answer is miraron