has / have

we have learnt this grammar weeks ago. But i can't the right answers from kc after i asked him to redo and redo and redo.

"He have a banana."
"It has a banana."
"She have a banana."

everytime i asked for redo, he must had put the 'have' in his sentences.
Then, finally we revised again for the 'has' and 'have'. Have him read out "He has, She has, It has... sentences".
And i asked him again for what we've revised.

He told me, "but there is the 'have' word in the choice, why we no need to use that word in our sentences?"

@@blurred.
it was the reason why he kept using the word 'have' in his 'He.. She.. It..' sentences.