From the example of computers, in the 1960s and 1970s only specialists used computers. In the 1980s came personal computers, and now there are portable ones.
由電腦的例子來看，六○到七○年代是專家在用大電腦，到八○年代，開始有個人電腦，到現在則是攜帶型電腦大行其道。