Breakdown of Sie hat das Zimmer nur für einen Monat gemietet.
haben
to have
das Zimmer
the room
der Monat
the month
für
for
Questions & Answers about Sie hat das Zimmer nur für einen Monat gemietet.
Why is it einen Monat and not einem Monat?
The preposition für always takes the accusative case. Since Monat is a masculine noun (der Monat), the indefinite article changes to einen in the accusative. Even though we are talking about a time period, the preposition strictly dictates the case.
Why is nur placed exactly where it is in this sentence?
The word nur (only) usually goes directly in front of the phrase it modifies. Here, nur für einen Monat emphasizes that the time period was only one month. If you moved it to say Sie hat nur das Zimmer..., it would change the meaning to say she rented only the room (and not the rest of the apartment).
Why does the past participle gemietet have an extra e before the final t?
Mieten is a regular (weak) verb, so its past participle is built with ge- + stem + -t. Because the stem (miet-) already ends in a t, German adds an extra e before the final ending (-et) simply to make the word easier to pronounce.
How can I remember whether to use mieten or vermieten here?