Add punctuation: The crisis has shown us how important it is that countries have an efficient and credible system which can step in when banks are failing
A: "The crisis has shown us how important it is that countries have an efficient and credible system which can step in when banks are failing.

Add punctuation: The historical texts that give us knowledge about the food that the Vikings ate typically date to after the Viking period
A: The historical texts, that give us knowledge about the food that the Vikings ate, typically date to after the Viking period.

Add punctuation: On next row from RS cast off the middle 232529 3339 sts 111214 1619 sts left each side Complete each side separately
A:
On next row from RS cast off the middle 23-25-29 (33-39) sts = 11-12-14 (16-19) sts left each side. Complete each side separately.