Questions & Answers about Nuo pienet koirat ovat nyt kotona.
Why do we use nuo instead of tuo?
Tuo means "that" (singular), but here we are talking about multiple dogs. Nuo is the plural form, meaning "those".
Why does the word for small (pieni) change to pienet here?
In Finnish, adjectives have to match the noun they describe. Because koirat (dogs) is plural and ends with the plural marker -t, the adjective must also take the plural -t ending to become pienet.
Why do we use the verb form ovat?
Ovat is the "they" form of the verb olla (to be). Because the subject "those small dogs" is a plural "they", the verb must match it. Note that in casual spoken Finnish, you will often hear people use the singular on instead of ovat, but ovat is the correct standard form.
I know koti means home, so why does the sentence use kotona?
Koti simply means "a home". The word kotona specifically means "at home". It uses a special ending (-na) to show location or a state of being. At this level, it is easiest to just memorize kotona as a fixed vocabulary word meaning "at home".