sign of the times

例句：

1. 1. The changing of the guard is asign of the times.
   卫兵换岗是时代变迁的标志。
2. 2. The rise of social mediais a sign of the times.
   社交媒体的兴起是时代变迁的标志。
3. 3. Thenew technology is a signof the times.
   新技术是时代变迁的标志。