In British English, the use of Simple Past and Present Perfect is quite strict. As soon as time expression in the past is given, you have to use Simple Past. But you have to use Present Perfect if there are no signal time words, you must decide if we just talk about an action in the past, or if its consequences in the present is important.
PATTERN : Subject + Have/Has + V3 (Past Participle)
1. We’re late. The game has already begun.
2. Shelley can’t go skiing anymore. She has broken her leg.
3. In the last few years, it has become more and more difficult to get into college.
4. She’s getting married in a week, and she hasn’t chosen her dress yet.
5. Have you sold car yet ?