You use preterite to describe an action that took place and was fully done, Ex. José entro a la habitación, you can see John went into the room, he completed the action. On the other hand, imperfect tense doesn't specificate if the action was completed, Ex. José entraba a la habitación, it doesn't tell us if José fully entered the room.
<h2>Hello!</h2><h2>

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Answer:
15. Maribel y yo <u>hablamos</u> inglés.
16. Tú <u>sabes</u> japonés.
17. Tú y tu hermanastra <u>estudian</u> francés.
18. Mi hijo <u>enseña</u> chino.
19. Yo <u>se</u> alemán.
20. Usted <u>saben</u> inglés.
21. Nosotros <u>aprendemos</u> italiano.
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Greetings 
Sincerely: <em><u>anapaulacbellido</u></em>
Answer:
Ella toca piano los miércoles.
Answer:
B. shop
Explanation:
This is because a Tienda In Cuba, Mexico, etc., is a booth, stall, or shop where merchandise is sold.