syukudai ha zenbu owarasetai kara, kyou ha sukosi sika nokosanai.

宿題は makes homework the topic of the sentence: as for the homework...

In Japanese, once something is introduced as the topic with は, it often does not need to be marked again as the direct object with を in the same sentence. The rest of the sentence is understood to be talking about that homework.

So this sentence is structured like:

• 宿題は = as for the homework,
• 全部終わらせたいから = because I want to finish all of it,
• 今日は少ししか残さない = today I won’t leave much of it.

If you used 宿題を, it would focus more directly on homework as the object of the verb, but here the speaker is setting it up as the overall topic.

全部 means all or all of it.

Here it goes with 終わらせたい, so:

• 全部終わらせたい = want to finish all of it

It refers to the homework. Japanese often leaves that connection implicit rather than repeating the noun.

So even though the sentence does not say 宿題を全部, that is basically the idea:

• 宿題は全部終わらせたい = As for the homework, I want to finish all of it

This is a very common question.

• 終わる = to end, to be finished
• 終わらせる = to finish something, to bring something to an end

So:

• 終わりたい would literally mean want to end or want to be over
• 終わらせたい means want to finish it

Since the speaker wants to finish the homework, the transitive form 終わらせる is the natural choice.

Examples:

• 授業が終わる = the class ends
• 授業を終わらせる = finish the class / bring the class to an end

So in this sentence:

• 全部終わらせたい = I want to finish all of it

It looks like one, and historically it comes from that pattern, but in modern Japanese 終わらせる is best treated as an ordinary transitive verb meaning to finish something.

So for a learner, it is most useful to think of the pair like this:

• 終わる = something ends
• 終わらせる = someone finishes something

In this sentence, you do not need to think of it as make it end every time. It simply means finish.

から means because.

So:

• 全部終わらせたいから = because I want to finish all of it

The first clause gives the reason for the second clause:

• Because I want to finish all the homework, today I won’t leave much.

This is a very common pattern:

• Aから、B。 = Because A, B.

For example:

• 眠いから、寝る。 = Because I’m sleepy, I’ll sleep.
• 忙しいから、行かない。 = Because I’m busy, I won’t go.

今日は means as for today or today, at least.

This second は marks today as a topic or point of contrast. It can suggest something like:

• today specifically
• at least for today
• speaking of today

So the sentence has two topical elements:

• 宿題は = as for the homework
• 今日は = as for today / today

This is normal in Japanese. The sentence is organizing information by topic rather than strictly following English word order.

A rough feel is:

• As for the homework, because I want to finish it all, as for today, I won’t leave much.

That sounds awkward in English, but it is natural in Japanese.

This is one of the most important grammar points in the sentence.

しか means something like nothing but, only, or no more than, but it is used with a negative verb.

So:

• 少ししか残さない literally feels like
• I do not leave anything except a little

Natural English:

• I’ll leave only a little
• I won’t leave much

The pattern is:

• Xしか + negative verb

Examples:

• 水しか飲まない。 = I drink nothing but water. / I only drink water.
• 一人しか来なかった。 = Only one person came.

So in this sentence:

• 少ししか残さない = leave only a little

Yes, a similar idea could be expressed with だけ, but the nuance is a little different.

• 少しだけ残す = leave just a little
• 少ししか残さない = leave only a little / not leave much

The しか + negative pattern often sounds a bit stronger or more emphatic. It highlights the small amount more clearly.

So:

• 少しだけ残す = neutral leave a little
• 少ししか残さない = leave only a little, with a stronger sense that the amount left is very small

Both are natural, but しか is a very common choice when emphasizing limitation.

Because the speaker is talking about leaving homework unfinished, not about homework remaining by itself.

Compare:

• 残る = to remain
• 残す = to leave something behind / leave something remaining

So:

• 宿題が少し残る = a little homework remains
• 宿題を少し残す = leave a little homework

In this sentence, the subject is implicitly I, and the object is the homework, so the transitive verb 残す is correct:

• 少ししか残さない = I won’t leave more than a little

The omitted object is the homework.

Japanese often avoids repeating nouns when they are already clear from context. Since the sentence begins with 宿題は, both 終わらせたい and 残さない are understood to be about the homework.

So the full idea is something like:

• 宿題は全部終わらせたいから、今日は宿題を少ししか残さない。

But repeating 宿題 again would sound unnecessary.

This kind of omission is extremely common in Japanese.

The subject is understood from context as I.

Japanese often leaves out pronouns like I, you, and he/she when they are obvious.

So the sentence naturally means:

• I want to finish all the homework, so today I won’t leave much.

You do not need 私は unless the speaker wants to emphasize I specifically.

The speaker is saying they intend to make a lot of progress today because they want to finish all the homework.

A natural interpretation is:

• Because I want to finish all the homework, I’m only going to leave a little for later today.
• Because I want to get all my homework done, I won’t leave much unfinished today.

The phrase 少ししか残さない especially suggests:

• there may still be a little left,
• but not much at all.

So the speaker is not necessarily saying I will finish everything today, but rather I will leave very little unfinished today.