Breakdown of sensei wa tsugi no shiken wa kinyou da to iimashita.
Questions & Answers about sensei wa tsugi no shiken wa kinyou da to iimashita.
Because there are really two layers:
- Main sentence: 先生は … 言いました
- Quoted content: 次の試験は金曜だ
The first は marks 先生 as the topic of the whole sentence.
The second は marks 次の試験 as the topic inside what the teacher said.
So the structure is roughly:
- As for the teacher,
- as for the next exam, it is Friday,
- he/she said.
This can look strange to English speakers, but it is normal in Japanese when one clause contains another.
Using は makes 先生 the topic: we are talking about the teacher and reporting what the teacher said.
If you used が instead:
- 先生が次の試験は金曜だと言いました
it would put more focus on the teacher as the one who said it, possibly contrasting with someone else.
Very roughly:
- 先生は = as for the teacher
- 先生が = the teacher is the one who said it
Both can be correct, but the nuance changes.
