There are 9 parts of speech or word classes in English language:
– nouns
– pronouns
– determiners
– verbs
– prepositions
– adjectives
– adverbs
– conjunctions
– interjections

There are 2 types of verbs:

– main verbs
(have their own meaning, can stand on their own)
Examples: walk, work, study, play, sing, etc.
I walk to school every day.

– auxiliary verbs (helping verbs)
(cannot stand on their own, needed to complete a sentence)
Examples: is,am,are,do,does,did,have,has,had
I am walking to school now.

Modal verbs:
– are part of auxiliary verbs
– cannot stand on their own, must be used with main verbs

10 modal verbs:
– can
– could
– will
– would
– shall
– should
– may
– might
– must
– ought to

1. Necessities & obligations (something that has to be done).
– All passengers must wear seat belts.
– You must work hard.
– We must be patient.

2. Rules & laws (something that someone has to obey)
– Visitors must not park outside the entrance.
– Residents must not make noise after 9 o’clock.
– Accidents must be reported to the safety officer.

3. Deductions/IikeIihood.
– She must think I’m stupid.
– You must be hungry.
– You must be very tired.

4. Invitations & encouragement to do something
– You must come and see us soon.
– You must go and see that film.

(+) Subject + must + base form
We must go.

(-) Subject + must not + base form
We must not go.

(?) Must + Subject + base form
Must we go?
– Yes, we must.
– No, we must not

(?) QW + Must + Subject + base form
When must we go?

‘Must’ can only be used with base forms.
We must go.
We must to go. (wrong)
We must went. (wrong)
We must goes. (wrong)
We must going. (wrong)

‘Must not’ is written as two words, not as one word.
I must not go.
I mustnot go. (wrong)

Non-action sentences:
– descriptions
You shall be a pilot one day.
– conditions
We shall be ready.
– locations
We shall be there tomorrow.

Sentence Patterns (Non-Action)

(+) Subject + shall + be + Noun / Adjective / Adverb of Place
You shall be a pilot one day.

(-) Subject + shall not + be + Noun / Adjective / Adverb of Place
We shall not be there tomorrow.

(?) Shall + Subject + be + Noun / Adjective / Adverb of Place
Shall we be there tomorrow?

1. Present ideals (something that is ideally done in a situation)
– They should reduce the price of petrol.
– The government should provide more public hospitals.

2. Advice and suggestions
– We should tell him.
– We should apologize to him.

3. Something that is likely or expected to happen.
– He should be here in ten minutes.
– According to his teacher, he should pass the exam.

(+) Subject + should + base form
You should come.

(-) Subject + should not + base form
(-) Subject + shouldn’t + base form
We should not leave.
We shouldn’t leave.

(?) Should+ Subject + base form
Should I inivite him?
– Yes, you should.
– No, you shouldn’t

(?) QW + Should+ Subject + base form
Where should we go?

‘Should’ can only be used with base forms.
We should come.
We should to come. (wrong)
We should came. (wrong)
We should comes. (wrong)
We should coming. (wrong)

‘Should not’ is written separately, not as one word.
He should not come.
He shouldnot come. (wrong)

(+) Subject + should+ be + Noun / Adjective / Adverb of Place
We should be there.

(-) Subject + should not + be + Noun / Adjective / Adverb of Place
(-) Subject + shouldn’t + be + Noun / Adjective / Adverb of Place
You should not be afraid.
You shouldn’t be afraid.

(?) Should + Subject + be + Noun / Adjective / Adverb of Place
Should he be the the team leader?