Bacon: Friendship doubles joy and halves pain.

Edison: Friendship can increase happiness and alleviate pain; because it can multiply our joy and share our worries.

Mao Yisheng: You must have methods and plans to study, so that you can get twice the result with half the effort.

Bacon: If you think twice before speaking, your words will be twice as good as before.

Franklin (USA): If man could accomplish half of what he wished for, his troubles would be doubled.

Lu Xun: A great mind should express such a spirit - greet tragic misfortune with a smile, and deal with all misfortunes with a hundredfold courage.

Leonardo da Vinci (Italy): The honor of a man's virtue is infinitely greater than the honor of his wealth. The reason why they didn't leave a trace in our memory is because they just wanted to use their estates and wealth to leave a name for future generations. Don’t you see how many people are poor in terms of money, but rich in virtue?

Plato (Greece): Not knowing one’s own ignorance is double ignorance.

Epicurus: Pleasure is not inherently bad, but some of its producers bring trouble many times greater than happiness.

Mayakovsky: I praise the present motherland, and I will praise its future three times more.

Suhomlinsky: Human love is a powerful force in education. Whoever can multiply the precious spiritual wealth of mankind with his own life and who can educate himself can educate his children well. The essence of educating children is to educate yourself, and self-education is the most powerful way for parents to influence their children.

Robert Wolson (USA): Creativity can be transferred. Research from the State University of New York shows that after a round of creative courses, students' creative thinking abilities almost doubled.