Learn Hardcore Spanish (Spain): Mi hermana compró una silla muy cómoda para su escritorio. - My sister bought a very comfortable chair for her desk.

Compró is the third person singular preterite form of the verb comprar ("to buy"). It indicates that the action—buying the chair—was completed in the past.

How does the possessive adjective su function in this sentence, and to whom does it refer?

In this sentence, su translates to "her" (referring to "mi hermana" or "my sister"). It shows that the chair was bought for her desk, implying ownership without repeating the subject's name.

Why is the preposition para used in the phrase para su escritorio, and what does it imply?

The preposition para is used to express purpose or intended use. In para su escritorio ("for her desk"), it indicates that the chair was purchased to be used with her desk.

How is the adjective phrase muy cómoda constructed, and how does adjective placement differ from English?

In Spanish, adjectives typically follow the noun they modify. Here, cómoda (comfortable) comes after silla (chair), and the adverb muy (very) is placed before cómoda to intensify it. This order contrasts with English, where adjectives and their intensifiers usually precede the noun (i.e., "a very comfortable chair").

Why is the indefinite article una used before silla, and what information does it provide?

The article una is an indefinite article that signals the noun is singular and feminine. It tells us that the sentence is referring to one non-specific chair rather than a particular, previously mentioned one.

How can I tell that hermana and silla are feminine, and how does this affect adjective and article agreement?

Both hermana and silla end in -a, which is a common indicator of feminine nouns in Spanish. Because of their feminine gender, the accompanying articles and adjectives (like una and cómoda) must also be in the feminine form to maintain proper agreement.