'Knows' in the Bible

And who knows whether he will be a wise man or a fool? Yet he will take over all my work that I labored at skillfully under the sun. This too is futile.

Who knows if the spirit of people rises upward and the spirit of animals goes downward to the earth?

What advantage then does the wise man have over the fool? What advantage is there for the poor person who knows how to conduct himself before others?

For who knows what is good for man in life, in the few days of his futile life that he spends like a shadow? Who can tell man what will happen after him under the sun?

Who is like the wise person, and who knows the interpretation of a matter? A man’s wisdom brightens his face, and the sternness of his face is changed.

The one who keeps a command will not experience anything harmful, and a wise heart knows the right time and procedure.

Yet no one knows what will happen because who can tell him what will happen?

Yet the fool multiplies words.No one knows what will happen,and who can tell anyone what will happen after him?