kono mondai ha mae ni benkyousita ki ga simasu.

I feel like I studied this problem before.

Breakdown of kono mondai ha mae ni benkyousita ki ga simasu.

• は: topic particle
• 勉べん強きょうする: to study
• に: time particle
• この: this
• 問もん題だい: problem
• 前まえ: before
• 〜た: past tense
• 気き が する: to feel; to have the impression

Questions & Answers about kono mondai ha mae ni benkyousita ki ga simasu.

What does this sentence mean in natural English?

A natural translation would be:

“I feel like I’ve studied this problem before.”
or
“I have the feeling I studied this question before.”

The key nuance is uncertainty / vague memory—you think you studied it, but you’re not 100% sure.

What does 気がします mean here, literally and grammatically?

Literally, 気 (き) means something like feeling / mood / sense.
〜気がします is a common pattern meaning:

• “I feel that 〜”
• “It seems to me that 〜”
• “I get the impression that 〜”

So:

• 勉強した気がします
  → I have the feeling (that) I studied (it).

Grammatically:

• 勉強した = “studied” (plain past form, modifying 気)
• 気 = “feeling, sense”
• が = subject marker (the “feeling” is what exists/occurs)
• します = “to do” → “to feel / to have (such a feeling)”

So the structure is:
[clause in plain form] + 気がする（します）
= “to have the feeling that [clause]”

Why is 勉強した in the past tense before 気がします? Shouldn’t it be present?

The tense reflects the content of the memory, not the time of “feeling”.

• You are now feeling that you studied this before.
• So the “feeling” verb します is in the present,
• but the action you’re remembering (勉強した) is in the past.

Compare:

• この問題は前に勉強した気がします。
  → I feel like I studied this before.

If you used 勉強する気がします, it would mean:

• I feel like (I’m going to / I want to) study (this).
  (future-ish intention/likelihood, not memory)

So the past tense here is correct and necessary.

Why is it この問題は and not この問題を?

は marks the topic, while を marks the direct object.

Here, the speaker is bringing up “this problem” as the topic of what they’re going to say:

• この問題は
  → As for this problem, / Regarding this problem,
  → This problem (at least)...

The actual “object” of 勉強した is understood from context (you studied this problem), but it doesn’t need to be marked with を because the sentence is organized around the topic:

• (私は) この問題は, (前に) 勉強した気がします。

Using を instead:

• この問題を前に勉強した気がします。

is not wrong, but it sounds a bit less natural because in this kind of reflective, personal statement, Japanese tends to make “this problem” the topic rather than just the grammatical object.

What exactly does 前に mean here? Is it different from just saying “before”?

前に (まえに) here is a time expression meaning:

• before, previously, earlier.

So:

• 前に勉強した = studied (it) before / studied it previously.

A couple of points:

1. 前 is a noun: “front; before (in time)”.
   With に, it becomes an adverbial time phrase: “at an earlier time”.

2. Compare with 以前（いぜん）に:

   • 前に is very common, casual, conversational.
   • 以前に sounds a bit more formal or written, and can refer to more distant past.

In this sentence, 前に = “at some time before now” without specifying when.

How is 気がします different from just using と思います?

Both express your personal judgment, but:

• 〜と思います
  → I think that 〜
  → More cognitive, about your opinion / reasoning.

• 〜気がします
  → I feel (like) 〜
  → More emotional / intuitive / vague, often used for impressions or hazy memories.

So:

• この問題は前に勉強したと思います。
  → I think I studied this problem before.
  (sounds like you’re making a reasoned statement)

• この問題は前に勉強した気がします。
  → I have the feeling I studied this problem before.
  (more like “I kind of remember / it rings a bell”; softer, more uncertain)

In many contexts you could swap them, but 気がします tends to sound gentler and less definite.

How is this different from saying この問題は前に勉強したことがあります。?

Good comparison:

• この問題は前に勉強したことがあります。
  Literally: There has been an occasion on which I studied this problem before.
  → Natural: “I’ve studied this problem before (at least once).”
  → This sounds like a fairly confident factual statement.

• この問題は前に勉強した気がします。
  → “I feel like I’ve studied this problem before.”
  → This expresses uncertainty; you’re not completely sure, you just have a vague memory.

So:

• ことがある → “I have (actually) done that before.” (experience, fact)
• 気がする → “I feel like / I seem to remember that I did that.” (impression, memory is hazy)

What is the role of the particle に in 前に here? Could we drop it?

In 前に, the に marks time: at / in / before (a point in time).

• 前 = “before (in time)”
• 前に = “at some earlier time / previously”

In this usage, you cannot drop に.
前勉強した気がします is ungrammatical.

Think of 前に as a fixed time expression: “(sometime) before”, needing に to function adverbially with the verb.

Why is there no explicit subject like “I” in the Japanese sentence?

Japanese often omits the subject when it’s clear from context.

In this case, who has the “feeling”? Obviously, the speaker. So there’s no need to say 私は.

The full version would be:

• （私は）この問題は前に勉強した気がします。

But 私は is usually dropped unless you need to contrast or emphasize it. The default interpretation in such sentences is “I”.

Is 気がします formal, casual, or neutral? How does it sound?

気がします with します is polite (the ます-form). It’s suitable for:

• talking to teachers
• coworkers
• people you’re not close to
• general polite conversation

The plain (casual) form is:

• 気がする
  • この問題は前に勉強した気がする。
    → casual; fine with friends, family, etc.

So:

• 気がします = polite, neutral, common in spoken Japanese.
• 気がする = casual, same meaning but used in informal settings.