Definition

Modal phrase: - Ought to; should have: Expresses an action or state that was expected, proper, or correct in the past but did not happen or was not done. It conveys a sense of obligation, advisability, or correctness that was not fulfilled, often leading to regret, criticism, or an analysis of an alternative scenario.

Usage Examples

• Expressing an unfulfilled past obligation or correct action:

  • Lẽ ra tôi phải học bài sớm hơn. (I ought to have studied earlier.)
  • Lẽ ra anh ấy nên xin lỗi cô ấy. (He should have apologized to her.)

• Analyzing a hypothetical better alternative:

  • Lẽ ra chúng ta đi đường khác thì đã không bị kẹt xe. (We ought to have taken a different route; then we wouldn't have been stuck in traffic.)
  • Lẽ ra hôm qua trời đã mưa. (It should have rained yesterday [based on the forecast, but it didn't].)

Advanced Usage

• "Lẽ ra... thì đã...": This common structure explicitly contrasts the unfulfilled action with its hypothetical consequence, often translated as "ought to have... then would have...".

  • Lẽ ra cậu nói sự thật thì đã không có chuyện gì. (You ought to have told the truth; then nothing would have happened.)

• "Đáng lẽ ra": A reinforced variant with the same meaning, adding slight emphasis. "Đáng lẽ ra" is interchangeable with "lẽ ra" in most contexts.

  • Đáng lẽ ra tôi không nên tin anh ta. (I really shouldn't have trusted him.)

Variants and Related Words

• Đáng lý ra (ph.): A synonym for "lẽ ra" and "đáng lẽ ra", meaning "rightfully should have".
• Phải chi / Giá như: Conjunctions meaning "if only", used to express wishes about the past, similar in sentiment but different in grammatical function from "lẽ ra".
• Nên: A modal verb meaning "should". While "nên" can refer to present/future advice, "lẽ ra + nên" specifically frames it as unfulfilled past advice.

Synonyms

• Should have: The most direct translation for expressing past advisability that was not followed.
• Ought to have: Slightly more formal than "should have", emphasizing moral obligation or correctness.
• Was/Were supposed to: Focuses more on a planned or expected action that did not occur.

Important Notes on Usage

• Tense: "Lẽ ra" always refers to the past. The action it modifies did not happen.
• Structure: It is typically followed by a verb phrase indicating the action that was expected (e.g., + Verb).
• Tone: It often carries a tone of regret, reproach, criticism, or analytical reflection on a missed opportunity or mistake.
• Not for Future: Do not use "lẽ ra" for future intentions. For future advice, use "nên" (should) or "phải" (must/have to) instead.
  • Correct (Future): Ngày mai bạn nên đi sớm. (Tomorrow you should go early.)
  • Incorrect (Future): ~~Ngày mai bạn lẽ ra đi sớm.~~

1. ought to