Levels & career tracks
Curso básico · A1–A2
Nivel A1.1 — IdentidadNivel A1.2 — Rutinas y entornoNivel A2.1 — Contando el mundoNivel A2.2 — Comparando y proyectandoIntermedio · B1–B2
Level B1.1 — Connecting experiencesLevel B1.2 — Narrating and describingLevel B2.1 — Arguing Current levelLevel B2.2 — NuanceProfesional / Avanzado · C1–C2
Level C1.1 — PrecisionLevel C1.2 — Register and discourseLevel C2.1 — StyleLevel C2.2 — Native masteryInglés técnico y especialización
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"Should have", "could have", "might have", and "must have" let you look back at the past and comment on it — criticize a decision, imagine an alternative, or make a confident guess about something you didn't witness. They're all followed by a past participle, and they never change form.
Why this matters This lesson connects directly to your progress: it covers should have / shouldn't have; could have / might have; must have (past certainty). Mastering this content lets you move forward confidently, and reinforces patterns you'll use again later. Take time to review every example before moving to the assessment — repetition is what actually locks knowledge in long-term.
01
The goals of this lesson.
02
You already use "must be" and "might be" to guess about the present. This lesson moves that same idea into the past — with "have" added, so you can comment on, criticize, or guess about something that already happened.
03
Use "should have + past participle" to criticize a past action or give advice about something that's already done — it's too late to change it now.
| Form | Use | Example |
|---|---|---|
| should(n't) have + past participle | criticism, regret about the past | You should have called me. |
Examples
04
Use "could have" or "might have + past participle" for something that was possible in the past but didn't happen, or that you're not sure about.
| Form | Use | Example |
|---|---|---|
| could/might have + past participle | past possibility, unrealized option | I could have helped you. |
Examples
05
Use "must have + past participle" when you're almost sure something happened, based on evidence — not a guess, a confident conclusion.
| Form | Use | Example |
|---|---|---|
| must have + past participle | confident deduction about the past | She must have left already. |
Examples
06
Read the text and answer the questions. You can try as many times as you want.
When Sarah arrived at the office, the lights were off and the door was unlocked. "Someone must have left in a hurry," she thought. She noticed a half-finished coffee on the desk. "They must have been called away suddenly — they wouldn't have left this otherwise."
Later, she found out her coworker had a family emergency. "I should have checked my phone earlier," Sarah said. "I could have helped if I had known sooner. She might have needed a ride to the hospital." Her coworker later explained everything was fine, and she shouldn't have worried so much.
1. What did Sarah notice when she arrived?
2. What did Sarah conclude about her coworker?
3. What was the real reason for leaving?
4. What does Sarah regret?
5. How did everything turn out?
💪 You can now criticize, speculate, and deduce about the past with real nuance. Keep going with B2!
07
The essentials of this lesson, summarized.
08
Key terms to remember.
used to criticize a past action that didn't happen
Collocations: should have known, should have told me, should have done
used for a past possibility that didn't happen
Collocations: could have been, could have done better, could have said
used for an uncertain past possibility
Collocations: might have forgotten, might have known, might have been
used for a confident deduction about the past
Collocations: must have known, must have forgotten, must have happened
used to say something was impossible in the past
Collocations: can't have known, can't have said that, can't have been easy
feeling relief after worry or stress has ended
Collocations: relieved to hear, feel relieved, visibly relieved
09
Tap the words in the correct order to form the sentence. Ungraded — repeat as many times as you like.
10
Tap the correct verb form to complete each sentence. The other options are conjugations from other tenses — on purpose, so you learn to tell them apart.
You should have me
She should have more
She might have the bus
She must have already
He must have his phone at home
11
Listen to the full dialogue with the speaker buttons first, then fill in the missing words from this lesson's real conversation. Ungraded — repeat as many times as you like.
Someone have left in a
I should my phone earlier.
12
You need at least 80% to unlock the next lesson. You can retake it as many times as you want — your best score is saved.
1. "You should have called me." — which one is correct?
2. What does this mean: "I could have helped you if you had asked."?
3. Select the correct match for: "She must have left already."
4. "I shouldn't have said that." — which one is correct?
5. What does this mean: "She might have missed the bus."?
6. Select the correct match for: "It must have rained last night."
7. "He can't have finished already." — which one is correct?
8. What does this mean: "We could have won the game."?
9. Select the correct match for: "He shouldn't have driven so fast."
10. "You must have worked really hard on this." — which one is correct?
Review — Lesson 47 What matches: "I wish I knew the answer."?
Review — Lesson 48 What matches: "She must be tired."?
13
You now criticize, speculate, and deduce about the past with real nuance. Next lesson: advanced contrast connectors, for presenting two sides of an argument.
00
Practice this lesson's vocabulary with a word search and flashcards. Ungraded — play as many times as you like.
Tap the first and last letter of a hidden word to find it. Los términos de varias palabras van sin espacios en el tablero (ej. "give up" aparece como GIVEUP).
Elige la respuesta correcta. Si aciertas, la tarjeta queda lista por hoy; si fallas, vuelve a aparecer pronto para reforzarla. Tu progreso se guarda en este dispositivo.