Confused about Has/Have

[Trejan]

Hi, I am confused about the has/have verbs. I need help.

I wanted to make a sentence couple of days ago but I wasn't sure.

Here is the sentence.

If my friend Mike haves an operation next week, how soon can he go home?

The problem with sentence is that If I use the "has" verb it doesn't give the message I want to cross over to the listener.

There is an another thing I want ask as well.

Which sentence is correct?

The children has gone.
The children have gone.

I will be greatful If you can find a solution.

Thank you

[Conchita]

Verb conjugation is very simple in English. There are, however, a few essential rules to observe:

Have -- present simple

I have
you have
he/she/it has
we have
you have
they have

1. If my friend Mike has an operation next week, how soon can he go home? (My friend => he)

2. The children have gone. (The children => they)

[Yankee]