The choice between 'has' and 'have' depends on its subject. Below is a chart showing which word to use with each type of subject:
|
|
singular |
plural |
|
1st person: I, we |
I have |
we have |
|
2nd person: you, you (all) |
you have |
you (all) have |
|
3rd person: he, she, it, they |
he/she/it has |
they have |
You'll notice that the only subject you should use "has" with is third person singular (he has, she has, it has). You should use "have" everywhere else.
The subject "Al and Sue" is third person plural (the same as "they"), so use "have."
Al and Sue have purchased a new home.
I hope this helps.