Quick Answer
Both lẽ ra and đáng lẽ convey the idea of 'should have' or 'ought to have' in Vietnamese, referring to a past action or state that did not happen. The key difference lies in their nuance: lẽ ra generally points to what was expected, planned, or intended but did not materialize, often expressing regret or disappointment. In contrast, đáng lẽ indicates what was proper, logical, or obligatory but was neglected, implying a stronger sense of blame, criticism, or impropriety.
Comparison Table
| Feature | Lẽ ra | Đáng lẽ |
|---|---|---|
| Meaning | Should have (expected, planned, intended) | Should have (proper, logical, obligatory, morally right) |
| Connotation | Regret, disappointment, missed opportunity, deviation from expectation | Blame, criticism, impropriety, moral obligation, deviation from correctness |
| Focus | What was supposed to happen vs. reality | What ought to have happened as the right/proper thing vs. reality |
| Usage Context | Planned actions, schedules, forecasts, general expectations. | Responsibilities, moral choices, logical conclusions, duties, appropriate behavior. |
| Example |
Lẽ ra tôi phải đến sớm hơn.
I should have arrived earlier (as planned/expected). |
Đáng lẽ anh ta phải xin lỗi.
He should have apologized (it was the proper/right thing to do). |
Detailed Explanation
The phrases lẽ ra and đáng lẽ are essential for B2 learners to express counterfactuals or unfulfilled past conditions. While both translate to 'should have' or 'ought to have', understanding their distinct nuances is crucial for accurate communication.
Lẽ ra
This phrase combines 'lẽ' (理 - lý, meaning reason, principle, logic) and 'ra' (出 - xuất, meaning to come out, to emerge). It literally suggests 'according to reason, it should come out this way'. Lẽ ra is used to talk about something that was expected, planned, or intended to happen, or was a logical outcome, but ultimately did not occur. It often conveys a sense of regret, disappointment, or a missed opportunity because the actual outcome diverged from the anticipated one. It is commonly followed by a clause explaining what actually happened or the consequences of the deviation. For example, if you missed a train, you might say: 'Lẽ ra tôi phải đến nhà ga sớm hơn.' (I should have arrived at the station earlier [as per my plan/expectation]).
Đáng lẽ
This phrase combines 'đáng' (當 - đương, meaning to be worthy of, to be proper, to deserve) and 'lẽ' (理 - lý, meaning reason, principle, logic). It conveys a stronger sense of what 'ought to have been' because it was the correct, appropriate, logical, or even morally obligatory action. When using đáng lẽ, there's often an implied criticism, blame (either self-blame or blaming others), or judgment for not having acted in the proper way. It highlights the impropriety or unreasonableness of the actual situation. For instance, if someone behaved rudely, you might say: 'Đáng lẽ anh ta không nên nói như vậy.' (He should not have spoken like that [because it was improper/rude]). Note that đáng lẽ ra is a common variant and carries the same meaning and nuance as đáng lẽ.
Example Pairs
I should have called him before coming (as I intended or was expected to).
I should have called him earlier to inform him (it was my responsibility).
It should have been sunny today (according to the forecast), but it's raining.
We shouldn't have gone out when it was raining heavily (it was not a proper/safe action).
The meeting should have ended at 4 o'clock (as per the schedule).
Everyone should have focused more during the meeting (it was proper professional conduct).
I would have had a cheap flight ticket if I had booked earlier (missed opportunity based on expectation).
You should have kept your promise (it's morally correct to do so).
He should have submitted the report by Friday (as per the deadline/expectation).
He should have taken responsibility for his mistake (it was the proper thing to do).
This train should have arrived at the station by now (according to the timetable).
You should have given your seat to an elderly person on the bus (it's a proper social courtesy).
I should have brought an umbrella (I expected rain, or it would have been wise).
We should always help people in need (it's a moral imperative).
I should have started exercising earlier (it was my plan or a good idea).
You should have told your parents the truth (it's the right and honest thing to do).
Common Patterns
Lẽ ra + Subject + Verb + (nhưng...)
This is a very common structure to express what was expected or planned, followed by a conjunction like 'nhưng' (but) to introduce the actual outcome.
Lẽ ra chúng tôi phải có mặt ở đó lúc 9 giờ, nhưng chúng tôi lại bị kẹt xe.We should have been there at 9 o'clock, but we got stuck in traffic.
Lẽ ra + Subject + đã + Verb
This structure is used to express a counterfactual past, indicating what would have happened if things had gone as expected or intended.
Nếu anh ấy không quên, lẽ ra anh ấy đã mang tài liệu rồi.If he hadn't forgotten, he would have brought the documents.
Đáng lẽ + Subject + Verb
This pattern directly states what was proper, logical, or obligatory. It often stands alone or leads to a consequence of the improper action.
Đáng lẽ cô ấy phải đến đúng giờ để không làm mất thời gian của mọi người.She should have arrived on time not to waste everyone's time.
Đáng lẽ ra + Subject + Verb
Adding 'ra' to 'đáng lẽ' is very common and carries the exact same meaning and nuance, often used for stylistic emphasis.
Đáng lẽ ra bạn phải xin phép trước khi mượn đồ.You should have asked for permission before borrowing things.
Common Mistakes
Mistake 1 — Misusing lẽ ra for a strong moral imperative
While lẽ ra can express regret, it's generally not strong enough for situations demanding a clear moral or ethical obligation. Using it in such contexts can sound too weak or imply a mere missed expectation rather than a failure of duty.
❌ Lẽ ra bạn phải tôn trọng người lớn tuổi.
✅ Đáng lẽ bạn phải tôn trọng người lớn tuổi.
Why it's wrong and how to fix it: Respecting elders is a fundamental moral and social obligation, not just an expectation. Đáng lẽ is more appropriate here as it conveys this sense of duty and proper behavior.
Mistake 2 — Using đáng lẽ for simple unfulfilled plans or expectations
Using đáng lẽ for a simple deviation from a schedule or a general expectation, where no strong sense of impropriety or blame is intended, can sound overly critical or dramatic.
❌ Đáng lẽ chuyến xe buýt phải đến lúc 8 giờ, nhưng nó bị trễ.
✅ Lẽ ra chuyến xe buýt phải đến lúc 8 giờ, nhưng nó bị trễ.
Why it's wrong and how to fix it: A bus being late is a deviation from its schedule (an expectation), not typically a failure of moral duty on the part of the bus. Lẽ ra accurately expresses this simple unfulfilled expectation without implying blame or impropriety.
Mistake 3 — Using lẽ ra when strong disapproval or a failure of duty is the focus
If the context implies that someone failed to do something they were duty-bound to do, or that an action was clearly inappropriate, đáng lẽ is the better choice for conveying that stronger sense of disapproval or judgment.
❌ Lẽ ra anh ấy phải báo cáo sự cố ngay lập tức.
✅ Đáng lẽ anh ấy phải báo cáo sự cố ngay lập tức.
Why it's wrong and how to fix it: Reporting an incident immediately is often a critical duty or a required procedure. Đáng lẽ more effectively conveys this sense of obligation and the potential impropriety or fault in not doing so, rather than just a missed expectation conveyed by lẽ ra.
Quick Quiz
Fill in the blank with lẽ ra or đáng lẽ:
- _____ tôi phải về nhà trước 10 giờ tối theo lời mẹ dặn, nhưng tôi lại ở lại chơi thêm một lúc.
Hint: This refers to an instruction or a rule given by a parent.
Answer
Correct answer: Đáng lẽ. Mẹ dặn suggests an obligation or a rule, making 'đáng lẽ' more fitting for something that 'should have been done' out of respect or obedience. The full sentence is: Đáng lẽ tôi phải về nhà trước 10 giờ tối theo lời mẹ dặn, nhưng tôi lại ở lại chơi thêm một lúc.
- Theo lịch trình, _____ chuyến bay đã cất cánh từ một giờ trước.
Hint: This refers to a schedule or a planned event.
Answer
Correct answer: Lẽ ra. "Theo lịch trình" clearly indicates an expectation based on a schedule, making 'lẽ ra' the correct choice. The full sentence is: Theo lịch trình, lẽ ra chuyến bay đã cất cánh từ một giờ trước.
- Anh ta _____ phải thừa nhận lỗi của mình ngay lập tức, chứ không phải che giấu.
Hint: This describes a morally correct action when someone makes a mistake.
Answer
Correct answer: Đáng lẽ. Thừa nhận lỗi is a matter of honesty and responsibility, a proper action. 'Đáng lẽ' emphasizes this moral correctness. The full sentence is: Anh ta đáng lẽ phải thừa nhận lỗi của mình ngay lập tức, chứ không phải che giấu.
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