F = maE = mc²2H₂ + O₂ = 2H₂O(点燃)a² + b² = c²sin²α + cos²α = 1To be, or not to be — that is the question.落霞与孤鹜齐飞 · 秋水共长天一色Practice makes perfect.1840 · 鸦片战争 1911 · 辛亥革命先天下之忧而忧,后天下之乐而乐光合作用:CO₂ + H₂O → 有机物 + O₂学而时习之,不亦说乎Where there is a will, there is a way.S = πr²北纬 30° · 七大洲 · 四大洋G = mg