Odpowiedź:
1) At the moment I am looking after my aunt's dog because she is abroad since last. She goes away on business quite often.
2) We walked in the mountains last weekend when the weather changed suddenly. We were surprised because we didn't check the weather forecast before leaving the hotel.
3) A: What time are you leaving for Wrocław tomorrow?
4) B: Well, I hope I will catch the early morning train, because I am helping my friend move into a new flat.