But there's something you'll note here also when I point out the case of the 2 s versus the 2 p, which is what I mentioned that I would be saying again and again, which is when we look at the hydrogen atom, the energy of all of the n equals 2 orbitals are exactly the same.

但是这里有一些事情你们也会注意到,当我指出2s和2p的情况，我之前提过,我会一次又一次的说，我们在观察氢原子的时候，2层轨道的所有n的能量,是完全相同的。

麻省理工公开课 - 化学原理课程节选

Every cell in your body has exactly the same DNA; that is if I could stretch out all the DNA and look at the base pair sequence, the sequences of bases along all the DNA in your chromosomes, they'd be identical in all the cells.

身体内每一个细胞都有完全相同的DNA,如果我把整条DNA展开,然后检查其碱基对的顺序,你体内每个细胞中染色体上,DNA的碱基对顺序,都是完全相同的

耶鲁公开课 - 生物医学工程探索课程节选