To appear out of thin air is to appear suddenly and unexpectedly as if out of nowhere.
Example: She expects money to just appear out of thin air.
Click here for more idioms and common expressions.
become less intense; become quieter; become weaker until it can't be perceived
Example: The sun's warmth fades away very quickly on a winter evening.
Be careful not to confuse effect with affect. Follow the link to find out more.
between two states
Example: He's neither tall nor short. He's in between.
Click here for more idioms and common expressions.