tsuuchou o mitara, omotta yori zandaka ga sukunakute odorokimashita.

When I looked at my bankbook, I was surprised that the balance was lower than I expected.

Breakdown of tsuuchou o mitara, omotta yori zandaka ga sukunakute odorokimashita.

• を: direct object particle
• が: subject particle
• 見みる: to look at
• より: comparative particle

Questions & Answers about tsuuchou o mitara, omotta yori zandaka ga sukunakute odorokimashita.

What does 見たら mean here, and why is it used instead of just 見て or 見た?

見たら is the -たら conditional form of 見る.

Here it means something like:

• when I looked
• after I looked
• upon looking

So 通帳を見たら means when I looked at my bankbook.

Why -たら?

• It often introduces something that happened after doing the first action.
• It can also carry a slight sense of discovery: when I looked, I found that...

That fits this sentence well, because the speaker checked the bankbook and then realized something surprising.

Compare:

• 通帳を見て、驚きました = I looked at the bankbook and was surprised.
• 通帳を見たら、驚きました = When I looked at the bankbook, I was surprised / Upon looking at it, I was surprised.

The -たら version sounds more natural here because it sets up the result of the discovery.

Why is を used with 通帳?

を marks the direct object of the verb 見る.

So:

• 通帳 = bankbook / passbook
• 通帳を見たら = when I looked at the bankbook

This is standard because 見る usually takes を for the thing being looked at.

What exactly is 通帳?