在 3D 世界里，所有的表演都需要一个舞台。Three.js 遵循“三剑客”原则：场景、相机、渲染器。
res[i] = stack[stack.length - 1]; // 易错点5：用at(-1)兼容性差，优先用stack.length-1
，更多细节参见同城约会
Speeding up virtual memory
However, the TaxPayers' Alliance has branded it a waste of money and the Covid-19 Bereaved Families for Justice UK said while the work being done was vital, public inquiries generally needed to become more efficient and less adversarial.