Which of these is preferable in a formal essay?
He thinks that the King will fall ill.
He thinks the King will fall ill.
This can be extended to other words, like knows, predicts, or concludes. But what troubles me is that there seems to be no accepted answer for all words.
For example, it sounds more natural to write
He predicts that it will rain today.
than without "that".
But it also sounds more natural to write
He thinks it will rain today.
than with "that".
