Untitled-99

might / may	might	might have	I may sing today. Yesterday I thought that I might sing. If I had practiced more, I might have sung better.
could / can	could	could have	He can live cheaply now. Last year, he could not live so cheaply. He could live here if he wanted to. If he had sold his car, he could have lived more simply.
would	would	would have	I would sing tonight if you wanted me to. Last week, I expected that I would sing more often. If I had been paid more, I would have sung more often.
will / shall	would		They will live with their kids in New York. When they arrived, they hoped that the kids would live with them in Hartford.
should / ought		should have ought to have	Sara should sing that folk song. She ought to sing it for the family first. She should have sung it at the party, but she was shy.
have to / must	had to		Max has to live in the city. He must live near his kids. When he lost his job, he had to live with his parents.
All modal auxiliaries in these two columns are followed by the base form of the main verb. Don't add -ed, -s or -ing: should live; can sing.		The auxiliaries in this column are followed by the past participle: ought to have lived; would have sung.

Notes:

Sometimes we use should or must to show a quess in the present:
This is the right address; Luis should live here.
This door has somebody else's name, so Luis must live upstairs.
We can use might have, may have, or must have, to show a quess in the past:
She's in town, so she might have sung at the festival.
She may have sung your favorite song.
It's March 15, so she must have sung in four cities in the past three weeks.