As a result, they become more powerful by a factor of two with every succeeding generation.

结果是，每一代电脑的性能都比前一代强两倍。

Carl Haub: If a couple has two children themselves, then they basically replace themselves. But if they have 1.2 or 1.3 or 1.4, every succeeding generation gets smaller and smaller.

卡尔•霍伯：如果一对夫妻要两个孩子，那在数量上刚好能取代他们，但是，如果一对夫妻平均只生1.2,1.3或1.4个孩子，那后代人口的数量会逐代减少。