ashita no hanabi no koto o kangaeru dake de, wakuwakushimasu.

direct object particle

Breakdown of ashita no hanabi no koto o kangaeru dake de, wakuwakushimasu.

• の: possessive case particle
• で: means particle
• 明日あした: tomorrow

Questions & Answers about ashita no hanabi no koto o kangaeru dake de, wakuwakushimasu.

Why is there の after 明日?

In this sentence, 明日 means tomorrow, and 明日の花火 means tomorrow’s fireworks or the fireworks tomorrow.

Here, の links nouns together, like ’s or of in English:

• 明日 = tomorrow
• 花火 = fireworks
• 明日の花火 = tomorrow’s fireworks

So 明日の花火 acts as one noun phrase.

What does the second の in 花火のこと do?

This の is also linking nouns, but the pattern X のこと has a special meaning: about X or the matter of X.

So:

• 花火のこと = about the fireworks / the fireworks as a topic

This is a very common pattern in Japanese:

• 彼のことを知っています。 = I know about him / I know him.
• 日本のことをもっと勉強したい。 = I want to study more about Japan.

In your sentence, 明日の花火のことを考える means to think about tomorrow’s fireworks.

Why is こと needed here? Why not just say 花火を考える?