— used to say that someone or something is or has become an important part of a situation, activity, etc.（重要的人或事物）出现，亮相，登场，问世
She was lonely for a while, but now there’s a new boyfriend on the scene. [=she has a new boyfriend]
她孤独了一阵子，但现在生活中有了一个新男友。
a popular singer who first burst on the scene last year
一位去年首次亮相的流行歌手
Our lives have changed a lot since computers have come/appeared on the scene.
自电脑问世以来，我们的生活发生了很大的变化