The modal verbs are , plus the semi-modals and phrasal alternatives ().

Modals share four grammatical properties: (1) no third-person (, not ); (2) followed by the bare infinitive (, not ); (3) questions and negatives without (); (4) no infinitives or participles — to fill the gaps, use substitutes: (for ), (for ):

Ability:

  • Present:

  • Past general ability:

  • Past single achievement: use , not : () In the negative, both work:

  • Future: :

Permission:

(neutral) — (more polite) — (formal). Granting/refusing:

Requests, offers, suggestions

  • Requests: ( = more polite)

  • Offers:

  • Suggestions:

Obligation and necessity:

@L3.6cmL8.6cm@ & obligation the speaker imposes or endorses:
& external obligation (rules, circumstances):
& prohibition: (= don’t do it)
& absence of obligation: (= it’s not necessary)

\(\ne\) . = paying is forbidden. = paying is optional. Confusing these reverses your meaning entirely.

Past obligation uses (there is no past of in this sense):

Advice:

Negative: .

Degrees of certainty (epistemic modality)

Modals also grade how sure the speaker is:

@lL7.6cm@ Certainty & Example
(sure it’s true) &
(confident prediction) &
(probable) &
(possible) &
(sure it’s false) &

The opposite of epistemic is , not : \(\leftrightarrow\)

Modal + + past participle looks back at past events:

  • : confident deduction —

  • : confident rejection —

  • : possibility —

  • : the right thing was not done (criticism or regret) —

  • : it was done, but was unnecessary —

  • : unrealized past outcome (see Chapter [ch:conditionals]) —

In speech, weakens to — never write : \(\to\)

Exercises

Choose the modal Choose the best option.

  1. You (mustn’t / don’t have to) shout — I can hear you perfectly.

  2. Visitors (mustn’t / don’t have to) feed the animals. It’s forbidden.

  3. I (could / was able to) finally fix the printer after two hours.

  4. That (can’t / mustn’t) be Tom at the door; he’s in Berlin.

  5. We (should / must) leave now, or we’ll hit traffic. (advice)

Modal + perfect Rewrite the idea using a modal perfect ( + participle).

  1. I’m sure Laura forgot the meeting.

  2. It was a mistake for you to lend him money.

  3. It’s possible that they took an earlier flight.

  4. It was unnecessary for you to print the documents (but you did).

  5. It’s impossible that Marco wrote this — it’s not his handwriting.

Error correction Correct one error in each sentence.

  1. She cans speak Russian fluently.

  2. You must to submit the form by Friday.

  3. I would of called you, but my phone died.

  4. Do you can help me with this box?

  5. Yesterday I must work until midnight.