A marked change or difference in behaviour or in a situation is very obvious or noticeable.

There was a marked improvement in my health when I gave up smoking. 戒烟后我的健康有了明显的改善。

Unemployment has fallen again, although the change is less marked than last month. 失业率再度下降，尽管降幅没有上个月明显。

The president spoke with passion for an hour, in marked contrast to his subdued address yesterday. 总统慷慨激昂地讲了一个小时，与昨天在议会上低声平和的发言形成了鲜明的对比。