Ya it's correct
All the underlined ones are correct
The proverb, "The cure for boredom is curiosity; there is no cure for curiosity." means that you will never be bored if you are curious because curiosity can never be taken away.
Sorry, it's only one sentence!! It's a start, though, and maybe it could help you to write the other 4 sentences.
Thoreau begins Civil Disobedience by saying that he agrees with the motto, "That government is best which governs least." Indeed, he says, men will someday be able to have a government that does not govern at all. As it is, government rarely proves useful or efficient.
