Apple Watch 走的也是这条路——将健康与通知两个功能一边升级、一边剥离出来，用户需要购买额外的配件，才能解锁 iPhone 更全面的体验。
Source: Computational Materials Science, Volume 267
，这一点在快连下载安装中也有详细论述
Hurdle Word 2 hintOffspring.
We even tried building hierarchies with 2-3 levels, but the number of shortcuts grew too fast for higher levels if we generated a full graph inside each cluster.