A couple of other things about hydrogen: hydrogen also, like other elements, has isotopes and we already saw that in 1766, Cavendish isolated atomic hydrogen and enunciated some of its properties.

一些关于氢的东西：,氢气，就像其他元素一样，有同位素，人们在1766年就发现了这一点，卡文迪许分离出原子氢,并且阐述了它的一些性质。

麻省理工公开课 - 固态化学导论课程节选

b OK. In this example I'd use b. All right, as b get-- b is the thing that's changing as I go along here, but it could be things like, how many elements are there in a list if the input is a list, could be how many digits are there in a string if the input's a string, it could be the size of the integer as we go along. All right.?

好，在这个例子里我会用，因为b是一直在变的东西,但是也可能是如下情况：,如果输入是数组的话,变化的就是数组的元素数，如果输入是字符串的话,变化的就是字符串的长度，如果是integer的话,可能就是这个数的大小，对不对？

麻省理工公开课 - 计算机科学及编程导论课程节选