Meaning & Usage
✨ Basic Meaning
“It would be good if…” / “What should I do?” / “What would be advisable?”
🎯 Primary Function
Expressing suggestions, recommendations, or asking for guidance.
📋 Grammar Structure
V (辞書形) + といい / V (た形) + らいい
I-Adj (ければ形) + いい
Na-Adj (なら) + いい / Na-Adj-に + なったらいい
V (ない形) + といい / V (なかった形) + らいい
🎭 Usage Contexts
Formal Situations
Used with です or でしょうか to maintain politeness, often for seeking advice from superiors.
Informal Situations
Very common in casual conversation, often shortened to どうしたらいい？ or V-たらいいよ。
Written Language
Common in emails, letters, or advice columns; less frequent in formal reports.
Spoken Language
Extremely frequent, forming the basis of everyday requests for and offers of advice.
💡 Common Applications
Seeking Advice (with interrogatives)
When paired with interrogative words (どう, 何, どこ, 誰), this structure functions as a question asking for the most advisable course of action. たらいい is overwhelmingly common here.
Example: どうしたらいいですか。 (Dō shitara ii desu ka.)
Giving Suggestions/Recommendations (たらいい)
V-たらいい is used to offer concrete, gentle advice or a suggestion to the listener, meaning “You should do X.” or “It would be good if you did X.”
Example: 水をたくさん飲んだらいいですよ。 (Mizu o takusan nondara ii desu yo.)
Expressing a Wish or Hope (といい)
V-る といい is typically used to express the speaker’s hope or wish regarding a future, often uncontrollable, event. It translates as “I hope that X happens.”
Example: 彼が成功するといいですね。 (Kare ga seikō suru to ii desu ne.)
Frequency
High (especially たらいい in conversation)
Difficulty
JLPT N3 / Intermediate
Tag:
Example Sentences
Example #1
プレゼン、どうしたらいいかアドバイスをください。
Furigana: プレゼン、どうしたらいいかアドバイスをください。
Romaji: Purezen, dou shitara ii ka adobaisu o kudasai.
English: Please give me some advice on what I should do for the presentation.
Example #2
まず、重要な点をメモにまとめたらいいですよ。
Furigana: まず、じゅうようなてんをメモにまとめたらいいですよ。
Romaji: Mazu, jūyō na ten o memo ni matometara ii desu yo.
English: First, it would be good if you summarized the important points in a memo.
Example #3
明日は晴れるといいですね。遠足に行けますから。
Furigana: あしたははれるといいですね。えんそくにいけますから。
Romaji: Ashita wa hareru to ii desu ne. Ensoku ni ikemasu kara.
English: I hope it clears up tomorrow, since we can go on the field trip.
Example #4
携帯が壊れたんですが、どこへ修理に出したらいいですか。
Furigana: けいたいがこわれたんですが、どこへしゅうりにだしたらいいですか。
Romaji: Keitai ga kowareta n desu ga, doko e shūri ni dashitara ii desu ka.
English: My phone broke, where should I take it for repairs?
Example #5
日本語能力試験に合格できるといいな。
Furigana: にほんごのうりょくしけんにごうかくできるといいな。
Romaji: Nihongo nōryoku shiken ni gōkaku dekiru to ii na.
English: I hope I can pass the Japanese Language Proficiency Test.
Example #6
もし迷っているなら、先生に正直に話してみたらいい。
Furigana: もしまよっているなら、せんせいにしょうじきにはなしてみたらいい。
Romaji: Moshi mayotte iru nara, sensei ni shōjiki ni hanashite mitara ii.
English: If you are lost, it would be good if you tried talking honestly to your teacher.
Example #7
転職を考えているのですが、どんな職種を選んだらいいでしょうか。
Furigana: てんしょくをかんがえているのですが、どんなしょくしゅをえらんだらいいでしょうか。
Romaji: Tenshoku o kangaete iru no desu ga, donna shokushu o erandara ii deshō ka.
English: I am considering changing jobs, what kind of occupation should I choose?
Example #8
疲れているときは、早く寝るに限る。早く寝るといいよ。
Furigana: つかれているときは、はやくねるにかぎる。はやくねるといいよ。
Romaji: Tsukarete iru toki wa, hayaku neru ni kagiru. Hayaku neru to ii yo.
English: When you are tired, the best thing is to sleep early. You should sleep early.
Example #9
失敗を恐れないといい。次につながりますよ。
Furigana: しっぱいをおそれないといい。つぎにつながりますよ。
Romaji: Shippai o osorenai to ii. Tsugi ni tsunagarimasu yo.
English: It would be good not to fear failure. It will lead to the next step.
Example #10
体調が悪いなら、無理せず休んだらいい。
Furigana: たいちょうがわるいなら、むりせずやすんだらいい。
Romaji: Taichō ga warui nara, muri sezu yasundara ii.
English: If you’re not feeling well, you should rest without pushing yourself.
Notes & Nuances
📌 Important Points
Use たらいい when asking for advice
When asking for advice, たらいい is almost always used, typically following an interrogative word (何, どこ, どう). This is the key usage of たらいい.
Example: どこで買ったらいいですか？ (Doko de kattara ii desu ka?)
Use といい to express wishes or hopes
The V-る/V-ない といい pattern is often used to express a personal hope or wish about a future outcome that is usually outside the speaker’s control.
Example: 雨が降らないといいな。 (Ame ga furanai to ii na.)
V-る といい for gentle, general recommendations
V-る といい can be used for giving general recommendations, often softer than V-たらいい. It emphasizes that the action is generally good or beneficial.
Example: もう一度確認するといいよ。 (Mō ichido kakunin suru to ii yo.)
⚠️ Common Mistakes
❌ X 何をするといいですか。
✅ V-たらいいですか
When asking for advice (e.g., “What should I do?”), the V-る といい form is unnatural. Always use V-たらいいですか with question words like どう or 何.
❌ Confusing it with V-てほしい or V-なさい.
✅ It is a suggestion, not a direct command or request.
While it translates to “should,” it is softer than the English equivalent and should not be used when demanding an action (use V-なさい or V-てほしい instead).
🏛️ Cultural Context
Politeness Level: Neutral to Polite. Adding です makes it polite (たらいいです). Using でしょうか makes the question more formal (たらいいでしょうか).
Social Situations: Ideal for situations requiring friendly, supportive advice, or when politely soliciting guidance from peers or seniors.
Regional Variations: The structure is standard Japanese, though regional dialects may use different conditional particles (e.g., V-ればいい is also standard but has a slightly different nuance).
🔍 Subtle Differences
V-たらいい vs. V-ばいい
V-たらいい is generally more versatile and used for specific actions or situations. V-ばいい (V-ればいい) often implies a logical conclusion or condition (“if you just do X, it will be fine”).
When to use: Use V-たらいい for concrete suggestions. Use V-ればいい when simplifying a problem or stating a general condition.
V-たらいい vs. V-たほうがいい
V-たらいい is a soft suggestion (“It would be good if…”). V-たほうがいい is a stronger recommendation, implying the action is the ‘better choice’ among alternatives, sometimes carrying a subtle warning if not followed.
When to use: Use V-たらいい for supportive, gentle advice. Use V-たほうがいい when you strongly believe an action is necessary or superior.
📝 Conjugation Notes
The ‘たら’ form uses the past tense (た-form) of the verb followed by ‘らいい’. The ‘と’ form uses the dictionary (plain) form of the verb followed by ‘といい’. The negative is V-ない といい or V-なかった らいい.
🔊 Pronunciation Tips
The ‘いい’ is pronounced with a long ‘i’ sound. When speaking casually, the ‘ii’ is sometimes dropped or slurred, especially when asking questions (e.g., どうしたら？).
🧠 Memory Tips
Think of たら (conditional: ‘if’) + いい (good) = “If you do this, it will be good.” And と (conditional: ‘when/if’) + いい (good) = “If this happens, it will be good.” (i.e., I hope).
Other Grammar
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