The document discusses English modal verbs. It explains that modal verbs are auxiliary verbs that express meanings like ability, permission, possibility, obligation, necessity, and probability. The modal verbs covered are can-could, may-might, should-ought, and must-have to. Each pair is explained in terms of their meanings, tenses, and usage. For example, can expresses ability, permission or possibility, while could is used in the past tense or in negative sentences. May expresses permission, doubt or possibility, and might is its past tense form. Should and ought express mild obligation and have the same meaning. Must expresses strong necessity or command, or strong probability. Have to is used to express necessity in all tenses.

1. ENGLISH MODALS

2. Modals
The modals of English
are auxiliary verbs. They
express particular
meanings.

3. Modals
CAN – COULD
MAY – MIGHT
SHOULD – OUGHT
MUST – HAVE TO

4. CAN - COULD
 1. Can has only two tenses- the present
tense can and the past tense could.
 2. Can may mean
 ability e.g. I can dance well.
 possibility e.g. anyone can lose money in
gambling.
 permission e.g. You can eat the food on the
table.

5. CAN - COULD
 3. Since can has only two tenses, the
expression to be able to is used as a
substitute for all tenses.
 4. Could is used in the same way as can
although could may be used in all negative
sentences in the past.
 e.g. Berto could climb the tree when he
was younger.

6. MAY- MIGHT
 1. May has only two tenses- the non-past tense may and the
past tense might.
 2. May is used to express
 a. Permission
 e.g. May I leave the room? You may go.
 b. Doubt or possibility
 e.g. The teacher may arrive late.
 c. Purpose
 e.g. They are working hard in their studies so that they
may pass the subject.
 They are practicing early for the dance contest so that
they may be allowed to go home before 5pm.

7. MAY- MIGHT
 3. The past-tense of may, might, is used in the
same way as may. e.g. He said that I might be
late.
 4. May has a special past tense form, obtained
by the use of the auxiliary verb have and the
past participle of the main verb. This is used only
to indicate possibility in the past.
 e.g. Elmer may have gone to school or
he may have gone home.

8. SHOULD- OUGHT
 1. Should and ought followed by an infinitive
are used to express a mild form of duty or
obligation.
 2. Should and ought have the same meaning
and can be used interchangeably.
 3. Should is more common than ought. e.g.
Students should study harder. You ought to
study harder.

9. SHOULD- OUGHT
 4. When the duty or obligation is in the past, should and
ought are followed by a perfect infinitive, the modal have
is used, followed by the past participle of the verb.
 5. The force of should and ought in the past tense form
is clearly negative, indicating that the duty or obligation
was not fulfilled. e.g. You should have finished your
book report. You ought to have done your assignment.
 6. Should and ought are also used to express probability.
 e.g. Your investment should produce big interest.
You ought to graduate next year.

10. MUST HAVE- HAVE TO
 1. Must has only one form, the present
tense.
 2. Must is used to express the following:
 a. Strong necessity or command
 e.g. You must pass the civil service exam.
 b. Strong probability
 e.g. This ballpen must be yours; your name
was printed on it.
 Marivic is adored by many; she must be

11. MUST HAVE- HAVE TO
 3. Have to is used to express necessity in
all tenses followed by an infinitive.
 e.g. The nurse have to take care of the patient.
 Lorenzo had to leave before midnight.
 4. It is possible to form a negative
sentence with to have by placing not after
the verb.
 e.g. Vincent has nothing to give.
 Ben hasn’t a peso.

12. MUST HAVE- HAVE TO
5. When to have is used together with
an infinitive to express necessity, the
tense carries do, does and did. They
are used to form all negatives and
questions.
 e.g. You do not have to leave.
 Do I have to do it?

13. TROUBLE SOME
WORDS