"The man does not laugh."
Translation:Mannen skrattar inte.
In this type of sentence, "inte" comes after the verb. The correct sentence would be "Mannen skrattar inte."
What is the difference between "skratta" and "skrattar"? Here, "skrattar" was right, while "skratta" was wrong.
(att) skratta is the infinitive, used like to laugh in English. (We like to laugh)
skrattar is the present, used like laugh or laughs in English (I laugh, she laughs)
The infinitive does not show time and cannot be used on its own without another verb.