news Life Is A Water Bottle After filling an empty water bottle with stones, a professor took out a box of pebbles and poured them into the water bottle. He gently 2019年8月1日
info Put down the cup in your hand A professor picked up a cup with water and asked the audience, "Guess how heavy is this cup?" "50 grams." "100 grams." "125 grams." Everyone 2019年8月1日