The word "done" in the first paragraph can be best replaced by "______".

A．it would take a long time to make a law in ancient Greek
B．it was Greek democracies who made the first human laws
C．once a human law comes into effect it is valid forever
D．old laws remained unchanged even after kings made new ones

A．the name "A Law of Nature" is not quite adequate
B．Laws of Nature have a lot of practical and theoretical value
C．Laws of Nature do not always accurately state the nature of matters
D．"law" has two different meanings