Meaning: Deduction concluding that something is certain
The past of must is must have (which is used with the past participle of a verb). Must have (which is often contracted to must've in speaking) is used to show a conclusion about the past.
Form: ‘must’+ present perfect of the principal verb (it refers to past time). (Must/’ve + past participle). Structure: modal + have+ past participle
Must have + past participle
CCQ’s:
1. Is she at work now? (No)
2. Do I think she has already gone home? (Yes)
3. Am I 100% sure about this? (No)
4. How sure am I? (99%)
5. Do I think it’s very likely (Yes)
6. What would I say if I was 100% sure? (She has gone out)
7. Am I talking about the past? (yes)
Phonological features: contraction of must+have to ‘ve. weak form /məs(t)/ weak form /həv/
Anticipated problems:
Pronunciation:
a) Because've sounds very much like of, some speakers sometimes write *must of when must've is actually the correct form.
b). In fast speech the 've in must've often changes to a sound that is easier to pronounce. As a result, must've often sounds something like "musta."
Form: students may confuse the meaning of the form as they tend to be more familiar with the use of must as a modal verb to express obligation (must can’t be used to express obligation in the past)
Students may struggle to understand that the form expresses deduction about the past
Meaning/concept: Learners may struggle to understand and pronounce the contraction ‘ve
Learners may add to (e.g she must’ve to gone out).
Meaning: Ss may think that must and have refers to an obligation that must be done in the future. This notion may be strengthened by the present use of must have rather than the past.
Form:
Students may incorrectly replace the past participle with the base form of the verb (she must have go out).
Pronunciation:
Must have becomes contracted in