Коль скоро секционное заседание закончилось, сессия вопросов и ответов начнётся.

Here коль скоро is a conjunction meaning roughly since, now that, or sometimes once.

A learner should know two things about it:

• It sounds formal, bookish, and a bit old-fashioned.
• In everyday speech, Russians would more often use раз, поскольку, or как только, depending on the exact meaning.

In this sentence, because the verb is закончилось rather than закончится, the sense is closer to now that the sectional meeting has ended than to as soon as it ends.

If you wanted a more everyday version, you might say:

• Раз секционное заседание закончилось, сессия вопросов и ответов начнётся.
• Как только секционное заседание закончится, сессия вопросов и ответов начнётся.
  This one shifts the meaning more clearly to a future as soon as idea.

Because Коль скоро секционное заседание закончилось is a subordinate clause, and it is separated from the main clause by a comma.

So the structure is:

• subordinate clause: Коль скоро секционное заседание закончилось
• main clause: сессия вопросов и ответов начнётся

Russian punctuation regularly uses a comma between these parts.

Russian does not have a separate tense that works exactly like the English present perfect.

So закончилось can correspond to either:

• ended
• has ended

depending on context.

Here it means the meeting is already over at the reference point, and that completed fact leads into the next event. So past tense is perfectly normal in Russian.

If the meeting had not ended yet and the meaning were truly future, Russian would normally use закончится instead:

• Как только секционное заседание закончится, сессия вопросов и ответов начнётся.

Because both verbs describe single completed boundary events:

• закончиться = to finish / to come to an end
• начаться = to begin / to start

The sentence is about one event ending and another one beginning, so perfective aspect is the natural choice.

If you used imperfective forms, the focus would shift toward process, repetition, or background description, which would not fit as well here.

For example:

• заканчивалось would suggest was ending
• начиналась would suggest was beginning / used to begin

That is not the main idea of this sentence.

This is a very important grammar point.

In the past tense, Russian verbs agree in gender and number

The subject of закончилось is заседание, which is neuter singular, so the verb is also neuter singular:

• заседание закончилось

Compare:

• доклад закончился — masculine
• лекция закончилась — feminine
• заседание закончилось — neuter
• встречи закончились — plural

But in the present and simple future, verbs do not show gender

Начнётся is just 3rd person singular future. It can go with a masculine, feminine, or neuter singular subject:

• урок начнётся
• лекция начнётся
• собрание начнётся

So there is no special feminine ending here for сессия.

Because Russian often uses the genitive case after a noun to show type, content, or associated material.

So:

• сессия вопросов и ответов = literally something like a session of questions and answers

Here:

• вопросов is genitive plural of вопрос
• ответов is genitive plural of ответ

This is a very common Russian pattern. Compare:

• чашка чая — a cup of tea
• центр города — the city center
• план урока — the lesson plan

English often uses noun stacking, like Q&A session, but Russian usually prefers a case relationship like this instead.

It is a fairly formal expression.

• заседание means a meeting, sitting, or formal session
• секционное comes from секция, meaning a section, especially at a conference, congress, or academic event

So секционное заседание usually means something like:

• section meeting
• sectional session
• breakout session
• sometimes panel session, depending on context

It sounds more formal and institutional than a casual word like встреча.

Yes. Russian word order is flexible.

This sentence begins with the subordinate clause:

• Коль скоро секционное заседание закончилось, сессия вопросов и ответов начнётся.

That order puts the background condition or timing first.

You could also say:

• Сессия вопросов и ответов начнётся, коль скоро секционное заседание закончилось.

That is grammatically possible, but it sounds a bit more marked and less natural in many contexts. Starting with the subordinate clause is smoother when you want to set up the situation first.

They can both be translated as session in English, but they are not identical in Russian.

• заседание is a meeting, often formal, administrative, academic, or official
• сессия is a session in the sense of a scheduled segment, event block, or organized part of a program

So the sentence distinguishes between:

• one formal meeting or section event ending
• another program segment, the Q&A session, beginning

English may use session for both, but Russian chooses different words to express the different functions.

Because in many Russian texts, ё is often written as е.

So:

• начнётся
• начнется

are the same word.

However:

• the pronunciation is still with yo
• learner materials, dictionaries, and careful writing often keep ё
• using ё can help avoid mistakes and ambiguity

So for learning purposes, начнётся is the more helpful spelling.