Miguel ha reparado un reproductor de mp3. (nunca) you answered(blank) changedquestion 2 with 1 blanksonia y su hermano han creado un blog. (todavía) you answered(blank) changedquestion 3 with 1 blankyo he adjuntado el archivo a este correo. (aún) you answered(blank) changedquestion 4 with 1 blanktú has navegado en la red. (nunca) you answered(blank) changedquestion 5 with 1 blanknosotros hemos descargado las fotos. (antes)

The correct way to turn sentences into negative form using the words in parentheses is as follows:

Miguel nunca ha reparado un reproductor de MP3.Sonia y su hermano todavía no han creado un blog.Yo aún no he adjuntado el archivo a este correo.Tú nunca has navegado en la red.Nosotros no hemos descargado las fotos antes.

Explanation:

The translation of the sentences is:

Miguel has never repaired an MP3 player. Sonia and her brother have not yet created a blog. I have not yet attached the file to this email. You have never surfed the web. We have not downloaded the photos before.

In Spanish there are two ways to make negative sentences:

Add the absolute denial "no" within the sentence. Use words that directly mean a negation such as "nunca."

For its part, the use of prepositions in Spanish is not as restrictive as in English, I mean, a preposition can be placed in more than one place within the sentence without modifying the meaning of it, here is an example with one of the sentences in the exercise:

Yo aún no he adjuntado el archivo a este correo.Yo no he adjuntado el archivo a este correo aún.

Enrique derribó la casa de muñecas de su hermana