Learn Hardcore Russian: Вчера мы смотрели интересный спектакль в театре. - Yesterday we watched an interesting play in the theater.

Вчера мы… – emphasizes when this happened.
Мы вчера… – slightly more neutral, just stating what you did yesterday.
Мы смотрели вчера… – can sound like you are contrasting with another time (for example: We watched it yesterday, not today).

So вчера is at the beginning simply as a natural, common way to start with the time information.

Why is the verb смотрели used and not посмотрели?

Russian verbs come in aspect pairs: imperfective and perfective.

смотреть → смотрели (imperfective, past plural)
посмотреть → посмотрели (perfective, past plural)

Imperfective (смотрели) focuses on the process or activity:

Вчера мы смотрели интересный спектакль в театре.
Focus: what you were doing yesterday; the activity itself.

Perfective (посмотрели) focuses on the completed result:

Вчера мы посмотрели интересный спектакль в театре.
Focus: you started and finished watching; the action is viewed as a whole, completed event.

In answers to questions like Что вы делали вчера? (What did you do yesterday?), the imperfective смотрели is more natural, because you are describing an activity you engaged in, not stressing that you finished it.

Why is it мы смотрели, not мы смотрел?

In Russian, past tense verbs agree with the subject in number (singular/plural) and, for singular, also in gender.

For смотреть in the past tense:

я смотрел (I watched – masculine speaker)
я смотрела (I watched – feminine speaker)
ты смотрел / смотрела
он смотрел
она смотрела
оно смотрело
мы смотрели
вы смотрели
они смотрели

With мы (we), the verb must be plural, so you use смотрели.
Мы смотрел is always incorrect.

How is the past tense form смотрели built from смотреть?

To form the simple past tense in Russian:

Take the infinitive: смотреть.
Remove -ть → смотре-.
Add past tense endings:
- Masculine singular: -л → смотрел
- Feminine singular: -ла → смотрела
- Neuter singular: -ло → смотрело
- Plural (any gender mix): -ли → смотрели

So смотреть → смотрели for мы, вы, or они in the past tense.

Why is there no separate word for were or was (like were watching)?

Russian does not use an auxiliary verb in the past tense the way English does. English has:

we were watching
we have watched
we had watched

Russian expresses these with a single past-tense verb form, plus verbal aspect:

мы смотрели – can correspond to we watched or we were watching depending on context.
мы посмотрели – often corresponds to we watched (and finished).

There is no form like мы были смотрели in standard Russian; that would be wrong in this sentence.

Why is it интересный спектакль, not интересная спектакль or интересное спектакль?

Adjectives in Russian must agree with the noun in gender, number, and case.

спектакль (play, stage performance) is masculine, singular.
In the sentence, it is the direct object (we watched what?), so it is in the accusative singular.
For masculine inanimate nouns in the accusative, the form is the same as the nominative.

The nominative/accusative masculine singular ending for adjectives is -ый / -ий:

Masculine: интересный спектакль
Feminine: интересная книга
Neuter: интересное письмо
Plural: интересные фильмы

So интересный спектакль is correct because спектакль is masculine.

How can I tell that интересный спектакль is in the accusative case if it looks like nominative?

For masculine inanimate nouns, the accusative singular form is identical to the nominative singular.

Nominative: интересный спектакль идёт в театре.
(An interesting play is on at the theater.)
Accusative: мы смотрели интересный спектакль.
(We watched an interesting play.)

You understand that интересный спектакль is accusative from the role it plays in the sentence: it answers что? (what?) after the transitive verb смотреть:

смотрели что? → интересный спектакль.

So grammatically it's accusative, but its form matches the nominative.

Why is it в театре and not в театр?

The preposition в can be followed by different cases depending on the meaning:

В + accusative: motion into a place (direction).
- Мы идём в театр. – We are going to the theater.
В + prepositional: being in/at a place (location).
- Мы в театре. – We are at the theater.
- Мы смотрели спектакль в театре. – We watched a play at the theater.

In в театре, театр is in the prepositional case: театре, used after в when you talk about location. The sentence describes where you watched the play, not where you were going, so в театре is correct.

Why is there no word for the before театр (like the theater)?

Russian does not have articles (no a / an / the).
Whether English would use the or a, Russian just uses the noun:

театр – can mean a theater or the theater.
в театре – can mean in a theater or in the theater.

The exact nuance (definite vs indefinite) is understood from context, not from a separate word. In this sentence, English speakers most naturally read it as at the theater, but Russian itself does not mark that difference.

What is the difference between спектакль and words like фильм or кино?

These words refer to different types of entertainment:

спектакль – a stage performance in a theater: a play, opera, ballet, etc. It is a live performance.
фильм – a film / movie (the actual work on screen).
кино – can mean cinema as an art form or the movies as a place or activity.

So:

Мы смотрели интересный спектакль в театре.
We watched an interesting (live) play in the theater.
Мы смотрели интересный фильм в кино.
We watched an interesting film at the cinema.

Using спектакль tells you this was a theatrical stage performance, not a movie.

Could I leave out мы and just say Вчера смотрели интересный спектакль в театре?

Yes. In Russian, subject pronouns (я, ты, он, мы, etc.) are often omitted when they are clear from context.

Смотрели is a past plural form.
It could refer to мы (we), вы (you plural / polite), or они (they), depending on the situation.

If the context already makes it clear who is being talked about, you can drop мы:

— Что вы делали вчера?
— Вчера смотрели интересный спектакль в театре.

In many neutral contexts, though, using мы is perfectly natural and sometimes clearer, especially in isolated sentences.

Is there any difference between Вчера мы смотрели интересный спектакль в театре and Мы вчера смотрели интересный спектакль в театре?

Both sentences are grammatically correct and mean essentially the same thing: Yesterday we watched an interesting play at the theater.

The nuance:

Вчера мы смотрели… – slightly more emphasis on yesterday as the time frame.
Мы вчера смотрели… – more neutral; common everyday word order.

In most everyday situations, the difference is minimal, and both are fine. Russian uses word order to shift emphasis, not to signal basic grammar like English does.

How do you pronounce смотрели and спектакль?

Смотрели:

Syllables: смо-тре-ли
Stress: смоТРЕли (on the second syllable: тре).
Pronunciation: approximately smat-RYE-lee (the о in unstressed position sounds closer to a).

Спектакль:

Syllables: спек-такль
Stress: спекТАКль (on так).
The final ль is a soft ль: tongue forward, softer than English l.
The кль at the end is a cluster; practice slowly: так-ли, then blend to такль.

So you get roughly: spek-TAK-lʲ (with the last l softened).