дельфины

дельфины

"Dельфины" means "dolphins" in English.

Here, 'дельфины' is used in the nominative plural form as the subject of the sentence.

Дельфины обитают в морях и океанах.

Dolphins inhabit seas and oceans.

Here, 'дельфинами' is used in the instrumental plural form as the object of the preposition 'за'.

Мы наблюдали за дельфинами с пляжа.

We observed the dolphins from the beach.

Here, 'дельфинах' is used in the prepositional plural form to specify 'о ком' (about whom).

Я часто думаю о дельфинах.

I often think about dolphins.