1. We last went to Spain three years ago.
=> It is three years since  we last went to Spain
2. We arrived in Budapest two days ago. (FOR)
=>We have arrived in Budapest for two days.
3. I have visited the Stone Forest once before. (SECOND)
=> This is the second time I have visited  the Stone Forest.
4. Dung is very fond of travelling. (KEEN)
=>Dung is keen on travelling
5. Turn off all the lights and you will not pay more money.
=> If you turn off all the lights, you will not pay more money.