Fill in the gaps with can, could and be able to.
1) The town hotel was full of visitors. We were in despair where to spend a night but at last we ___________ find two vacant rooms.
2) Before the bridge was built we only ___________ (get) to the island by ferry.
3) ______ she _______ come to our office tomorrow?
4) The fishing boat sank but fortunately the fisherman ___________ swim to the shore.