mensetsu no mae ni shinkokyuu o shite kara, heya ni hairimashita.

Before the interview, I took a deep breath and then entered the room.

Breakdown of mensetsu no mae ni shinkokyuu o shite kara, heya ni hairimashita.

• に: destination particle
• の: possessive case particle
• に: time particle
• 部屋へや: room

Questions & Answers about mensetsu no mae ni shinkokyuu o shite kara, heya ni hairimashita.

Why is の used in 面接の前?

の links the noun 面接 to the noun 前.

• 面接 = interview
• 前 = before / front

In this pattern, X の 前 means before X.

So:

• 面接の前 = before the interview

This is very common with time-related nouns:

• 授業の前 = before class
• 食事の前 = before a meal

What does 前に mean here, and why is に added?

前 by itself means before or front, but in time expressions, に often marks the point in time relative to something.

So:

• 面接の前に = before the interview

You can think of に here as helping mark when the action happened.

The pattern is:

• Noun + の + 前に + action
• Verb dictionary form + 前に + action

Examples:

• 面接の前に、深呼吸をする = to take a deep breath before the interview
• 寝る前に、水を飲む = drink water before sleeping

Why is it 深呼吸をして? Why does 深呼吸 take を?