AT is used to say where sth/sb is or where sth happens(在某處發生):
1. We changed at the next stop.
2. They arrived late at the airport.
3. at the roundabout take the third exit.
AT is used to say where sth/sb is or where sth happens(在某處發生):
1. We changed at the next stop.
2. They arrived late at the airport.
3. at the roundabout take the third exit.
