Who will be in charge in ______ of our boss?

With several rounds of talks, the union leaders successfully          an agreement for a shorter working week.

 The experienced teachers try their best _____ the younger ones _____experience.

Studies show that people are more __________ to suffer from back problems if they always sit before computer screens for long hours.

The native Canadians lived in __________ with nature, for they respected nature as a provider of life.