They came to think about algebraic objects associated with knots/links that are invariant under isotopy c .J.W.Alexander came up with the first good such quantity, the Alexander polynomiald .
我认为剩下的人里面绝大多数对于一个中
人只身
奋斗所遭遇的种种困难、辛酸、挫折、
落、压抑、他人的期望，成功和兴奋没有
，更遑论理。
