KJV:
These have power to shut heaven, that it rain not in the days of their prophecy: and have power over waters to turn them to blood, and to smite the earth with all plagues, as often as they will.
NASB:
These have the power to shut up the sky, so that rain will not fall during the days of their prophesying; and they have power over the waters to turn them into blood, and to strike the earth with every plague, as often as they desire.