Te Okimasu and sentence ending with Kara

Question

I have some questions to asks on Japanese grammar.

1. What does

次{つぎ}の会議{かいぎ}までに何{なに}をしておいたらいいですか
tsugi no kaigi made ni nani o shite oitara iidesu ka

mean? How is this question conditional (oitara)? From my understanding this sentence means, "What should I do before the next meeting?"

2. 千円、ここに置いておくからね。

For this sentence may I know what kara at the end of sentence means? As I understand, the whole sentence means "I will leave 1,000 yen here for you"

3. How do you say te-form, conditional form, potential form and passive form in Japanese? For eg. Futsukei is plain form. Teineikei is polite form.

Answer 1

次の会議までに何をしておいたらいいですか

Your translation of "What should I do before the next meeting" is pretty accurate.

The break down of しておいたら is as follows:

する = to do

しておく = te-form of verb + おく. This construction means 'to do verb in advance or in preparation for something'. In this sentence we're doing something in preparation for the next meeting.

しておいたら is the たら conditional form of しておく.

So the おい (おく) part has nothing to do with the conditional.

The conditional part is how the meaning of 'should' is conveyed.

Verb in past tense + ら　+ いいですか i.e. たら form of verb + いいですか, literally means "if I do verb will it be okay", i.e. "should I do verb".

Adding 何 to the phrase, 何をしておいたらいいですか, is impossible to translate word for word into good English. But it would be something like "What, if I do it, will be okay". Which more normally translates to "What should I do".

Please ask parts 2 and 3 as separate posts.