Verb dictionary form + 前に + Main clause

[Before Doing ~ (Clause)]

Connection: Verb dictionary form + 前に + Main clause

This is the clause-level use of 前に. A verb clause comes before 前に, modifying the time of the main clause.

CRITICAL RULE: The verb before 前に ALWAYS uses the dictionary form (non-past), NEVER the た-form, even when the main clause is in the past tense.

This is different from とき, which can use past or non-past depending on meaning. With 前に, the action before 前に hasn't happened yet (from the perspective of the time reference), so it's always dictionary form.

Structure: [Verb phrase dictionary form] + 前に、[Main clause]

Examples:

日本に来る前に、日本語を勉強しました。(Before coming to Japan, I studied Japanese.)

会社に入る前に、アルバイトをしていました。(Before entering the company, I was doing part-time work.)

寝る前に、本を読みます。(Before sleeping, I read a book.)