— used to say what is actually done or what the actual effect or result of something is事实上；实际上
The software is designed to block pornographic Web sites, but in practice [=in reality], it blocks many other sites as well.设计这个软件是用来封锁色情网站的，但在实际运用当中，它也封锁了很多其他网站。
In actual practice, people sometimes forget to take their medication.实际上，人们有时会忘记吃药。