Answer: 4- Option c: fueron.
5- option b: I went to Bogota.
Step-by-step explanation:
4) We need to complete the sentence:
"Ellos _____ al correo para comprar sellos"
and the translation would be:
"They____ to the mail office to buy stamps"
The right option here is the plural for "ellos", the option C, Fueron.
The complete sentence is "Ellos fueron al corre para comprar sellos".
5) The sentence "Fui a Bogota" is translated to "I went to Bogota"
Where the "i" part in spanish, "yo", is implicit in the word "fui", so the right option is B, "i went to Bogota"