Nelson Mandela, former president of South Africa, devoted himself        to making the black and white equal.

Work gets done ________ when people do it together, and the rewards are higher too. 

Football is very important to me, but _____ is our friendship.

Life is stressful, and complaining may be considered by many as an extension of being________normal.

 Zhengnengliang, or positive energy, _______a term used in the book Positive Energy by Richard Wiseman, has developed into a popular phrase in Chinese society where people approach life with optimism and confidence.