💡 How it works
Read the evidence, set your certainty
When we don’t know what happened, we deduce from the evidence. The modal shows how sure we are; the form is always modal + have + past participle. Pick a case and slide the thermometer. (El modal marca la certeza; la forma no cambia.)
1 · Choose a case
2 · Slide the certainty thermometer
modal + havepast participle
⚠️ The opposite of must have is can’t have — never mustn’t have.
⭐ Look-alikes & special cases
Four things that trip people up
👩🏫 For the teacher — how this page maps to the manual
- Explore is Grammar 5's certainty thermometer: the modal marks how sure the speaker is (must have ≈95% yes → can't have ≈95% no). The special-cases card covers could have's two jobs, should have (not deduction), and the continuous & passive forms.
- Build is productive: students assemble a deduction by choosing the modal that fits the certainty, then transform situations into deductions (exercise C), with validation.
- Drill merges the quizzes into one graded engine (★ how-certain/choose · ★★ fix the error/complete · ★★★ could-have, continuous & passive) with a score and streak.
- Works offline. Reading/writing only — no audio.
🔧 Your turn to produce
Build a deduction
Read the evidence and the certainty, then choose the modal that fits. The machine builds the deduction — guess before you check.
Which modal fits the certainty?
Built: 0
🎯 Graded practice
Drill — one flow, three levels
★ how certain? & choose · ★★ fix the error & complete · ★★★ could-have, continuous & passive. Keep your streak alive. (Igual escalera que tu Cuaderno de tareas.)
Score: 0🔥 0