Help me, its french iiregular verbes: DEVOIR, VOULOIR, and POUVOIR

Culture of france  and of the  french people  has been shaped by  geography, by profound  historical events, and by foreign and internal forces and groups.  france, and in particular  paris, has played an important role as a centre of  high culture  since the 17th century and from the 19th century on, worldwide. from the late 19th century, france has also played an important role in  cinema,  fashion,  cuisine,  literature,  technology,  social science  and  mathematics. the importance of french culture has waxed and waned over the centuries, depending on its economic, political and military importance. french culture today is marked both by great regional and socioeconomic differences and strong unifying tendencies. a global opinion poll for the  bbc  saw france ranked as the country with the fourth most positive influence in the world (behind germany, canada and the uk) in 2014.