После лекции мы перешли к обсуждению.

After the lecture, we moved on to the discussion.

Breakdown of После лекции мы перешли к обсуждению.

• к: to
• мы: we
• после: after
• лекция: the lecture

Questions & Answers about После лекции мы перешли к обсуждению.

Why is it после лекции and not после лекция?

Because после requires the genitive case.

The base form is лекция.
After после, it changes to the genitive singular:

• лекция → nominative
• лекции → genitive singular

So:

• после лекции = after the lecture / after the lecture ended

This is a very common pattern in Russian:

• после урока = after the lesson
• после фильма = after the film
• после работы = after work

Is лекции singular or plural here?

Here it is singular, even though лекции can also be a plural form in other contexts.

Why do we know it is singular here? Because после takes the genitive, and the genitive singular of лекция is лекции.

So in this sentence:

• после лекции = after the lecture (singular)

Not:

• after lectures (plural)

Context and the grammar after после make that clear.

Why is it к обсуждению and not обсуждение?