Question: I've been taught that words such as qué and dónde have accents on them only in questions. But I sometimes see them with accents in statements. Why is that? For example, here's one sentence I saw: El Banco Central no aclaró cuántos dólares vendió. (The Central Bank did not make clear how many dollars it sold.)
Answer: It is true that words such as qué, dónde, cuánto, cuál, quién and cómo have orthographic accents when they're part of questions, and they generally don't have accents otherwise. However, the accent is retained even in a statement when used as part of an indirect question. (An orthographic accent is one added not to indicate how a word is pronounced, but to distinguish it from the same word without the accent.)
Some indirect questions are obvious, as in this sentence: Quisiera saber dónde puedo encontrar algún programa para convertir archivos de MP3. (I would like to know where I can find a program for converting MP3 files.) However, most are less obvious, as in the example you gave.
Here are some other examples of indirect questions where an interrogative (accented) form of a word is used:
- No sé dónde está. (I don't know where he is.)
- Saben qué va a pasar. (They know what is going to happen.)
- Ella me dijo por qué se cambió su nombre. (She told me why she changed her name.)
- Es difícil decir exactamente cuántos cadáveres había. (It's difficult to say exactly how many corpses there were.)
- La comisión va a investigar quién es el responsable. (The commission will investigate who is responsible.)
In some cases, as in the second example above, the accent is needed to clarify the meaning of the word that is being used, and the meaning changes without the accent. Note the significant difference, for example, between sé que va a comer (I know that he is going to eat) and sé qué va a comer (I know what he is going to eat).
Similarly, in a statement, como typically can be translated as "like" or "as," while cómo can be translated as "how." Me encanta cómo toca el piano como Liberace (I love how he plays the piano like Liberace).