kinou wa densha no oto ga ookikatta node, watashi wa mimi o fusagimashita.

Because the train noise was loud yesterday, I covered my ears.

Breakdown of kinou wa densha no oto ga ookikatta node, watashi wa mimi o fusagimashita.

• は: topic particle
• 私わたし: I
• を: direct object particle
• が: subject particle

Questions & Answers about kinou wa densha no oto ga ookikatta node, watashi wa mimi o fusagimashita.

Why is は used after 昨日 instead of に?

In Japanese, は can mark the topic of the sentence, not just the subject. By saying 昨日は, you’re setting “yesterday” as the topic—“As for yesterday,…” This is more common in everyday speech when you want to comment on the conditions or events of that time. You could say 昨日に to mean “on yesterday,” but that’s more formal/time‐specific and less about making yesterday the topic.

What role does の play in 電車の音?

The particle の connects two nouns to show a relationship—often possession or attribution. In 電車の音, it literally means “the sound of the train.” Here, 電車 attributes what kind of sound you’re talking about. Think of it like the genitive (‘of’) in English.

Why is が used after 音 instead of は?

After 音, が marks the subject in the subordinate clause 電車の音が大きかったので. You’re simply stating a fact there (“the train’s sound was loud”), so you use が for a new or focusing subject. If you used は, it would imply contrast or already-known info.

How does 大きかった relate to the adjective 大きい?