Дорога была построена раньше, чем дом.

the house

Breakdown of Дорога была построена раньше, чем дом.

• быть: to be
• дорога: the road
• раньше: earlier

Questions & Answers about Дорога была построена раньше, чем дом.

Why is the verb phrase была построена used here instead of an active form like построили?

The phrase была построена is the past passive voice, which emphasizes the road (дорога) as the subject and the completed action, rather than who performed it. In Russian, the passive past is formed with the auxiliary быть (in the past tense) + past passive participle. An active alternative could be Кто-то построил дорогу раньше, чем дом, but that shifts the focus onto the unnamed doer (кто-то).

How do you form the past passive participle построена?

Start with the perfective infinitive построить, remove -ть, add the suffix -ен- (or -ён- after certain consonants), and then attach the gender ending. Since дорога is feminine, you get:
постро- + ен- + а → построена.

Why is there a comma before чем? Is it always required?

Yes. In comparative constructions with a comparative adverb + чем (e.g., раньше, чем), a comma precedes чем to mark the comparison:
Я пришёл раньше, чем он.
Omitting the comma in standard written Russian in this context is considered incorrect.

What is the role of раньше, чем here? Can I just use раньше alone?