Answer:
You use preterite form when talking about past actions
ex: Ella caminó por el parque
You mainly use the imperfect tense when talking about repeated, usual, or habitual actions in the past
ex: Los sábados yo jugaba con mi vecino
Tú casa es grande.

The difference between "tú" and "usted" depends on the formality. "Tú" is used <u>when talking to friends or relatives (informal)</u> while "usted" is used <u>when talking to older people or a person of high social rank (formal)</u>.
In this case we want to write the <u>informal</u> form of "tú", so we use "tú". Also, when dealing with <u>permanent states</u>, the verb "ser" (to be) is used.
Answer:
increible pero no fue lo mismo sin ti
Explanation:
B.
Me gustan mucho las tortas de chocolate por que son muy deliciosas