translation.en: But if it wasn't for Mr. Euler -- who wrote almost 70 volumes of mathematics and had 13 children, who he apparently would dandle on his knee while he was writing -- if it wasn't for Mr. Euler, there wouldn't perhaps be these invariants.
translation.zh: 但如果没有欧拉先生 写下了近70卷数学著作 还有13个子女 显然在他写作时 承欢膝下 如果没有欧拉先生 可能就不会有这些不变量了