Learn Russian: Вчера мы были там, а сегодня мы здесь. - Yesterday we were there, and today we are here.

In Russian, the present tense of the verb "to be" (am, is, are) is usually skipped. So, сегодня мы здесь literally means "today we here." But in the past tense, you must use the verb! That's why вчера (yesterday) is paired with the past tense verb были (were).

How do I know whether to use был, была, or были with вчера?

Past tense verbs in Russian change based on the gender and number of the subject. Since the subject here is мы (we), which is plural, you use the plural past tense form были. If the sentence was about "he," you would use был, and for "she," you would use была.

The translation says "and today," but isn't the word for "and" usually и? Why use а here?

а is a special connecting word that can mean "and" or "but" when you are pointing out a contrast. Because this sentence contrasts where we were yesterday (вчера) with where we are today (сегодня), а is the perfect fit. Using и here would sound unnatural, like you are just listing facts rather than comparing two different situations.

Why does сегодня have a "г" in it if the audio pronounces it with a "v" sound?