Learn Hardcore Russian: Я прочитал первую статью, а потом перешёл к следующей. - I read the first article, and then I moved on to the next one.

Прочитал is the perfective past tense of прочитать, indicating that the action (reading the first article) is completed. Читал is the imperfective past, describing the process or a habitual action without focusing on its completion. Since you want to say “I have finished reading the first article,” you use прочитал.

Why is первую статью in the accusative case?

The verb прочитать requires a direct object, which in Russian takes the accusative case. Статья is a feminine noun ending in -я, so in the accusative singular it changes to статью, and the adjective первый agrees with it, becoming первую.

Why is there a comma before а потом?

In Russian, when you connect two independent clauses (each with its own subject and verb) with a coordinating conjunction like а, you put a comma before the conjunction. Here, Я прочитал первую статью and потом перешёл к следующей are independent clauses, so you write …, а потом ….

What is the difference between а потом, потом, затем, and после этого?

• Потом is a simple adverb meaning “then” or “afterwards.”
• А потом adds a slight contrast or emphasis, like “and then” or “but then.”
• Затем is more formal or literary, also meaning “then” or “after that.”
• После этого is a phrase with the preposition после (“after this”), often followed by a noun or pronoun, e.g. после этого я перешёл…. It’s longer and more explicit.

Why is к следующей in the dative case?

The verb перейти (“to move on” or “to switch”) is used with the preposition к and takes the dative case to indicate direction toward something. Следующая статья in the dative singular becomes следующей.

Why do the adjectives первую and следующей have different endings?

Adjectives in Russian agree with nouns in gender, number, and case.
• Первую is accusative feminine singular (matching статью).
• Следующей is dative feminine singular (matching к следующей статье).
Each ending reflects both the feminine gender of статья and the respective case required by the verb.

Could I reorder the sentence or use a different conjunction?

Yes. Russian word order is relatively flexible, and you could say:
• Я прочитал первую статью, потом перешёл к следующей. (omit а)
• Прочитав первую статью, я перешёл к следующей. (use a participle clause)
• Я прочитал первую статью и потом перешёл к следующей. (use и instead of а)
Each variant is grammatically correct; the original phrasing with а потом simply adds a subtle contrast and conversational flow.