Modal In Simple Present and Past Tenses

Modal Auxiliary Verb in Simple Present Tense

Verb Sentence
S + modal auxiliary + V bi + (rest of sentence)
Example:
We can go to the beach on time by bus.
We must go to the beach by bus.
We may go to the beach by bus.
We must can (X): We must be able to do all homeworks well.
Nominal Sentence
S + modal auxiliary + be + 3C
Example:
We can be there on time bu bus.
We must be there on time.
We may go be there on time.
We may can (X): We may be able to do all homeworks correctly.

Modal Auxiliary Verb in Simple Past Tense

Verb Sentence
S + modal auxiliary + V bi + (rest of sentence)
Example:
We could go to the beach on time by bus yesterday.
We had to go to the beach by bus.
We might go to beach by bus.
We had to can (X) : We had to be able to do all homeworks well.
Nominal Sentence
S + modal auxiliary + be + 3C
Example:
We could be there on time by bus last week.
We had to be there on time last week.
We might go be there on time.
We might can (X) : We might be able to do all homeworks correctly last week.