Official Picks Canada, SovietPRAGUE (AP) - Jack Rox-burgh, president of the Canadian Amateur Hockey Association, told Czechoslovakian reporters that the world hockey championships will be decided between Canada and the Soviet Union.CTK, the official Czech news agency, quoted Roxburgh as saying he is certain that the Soviets will be the toughest opponents in next month’s tourna-, ment.Roxburgh said the Soviet Dlayers are steadily getting better and that it will be ex-tremely difficult for Canada to beat them.He feels the Czech team this vear is sorpewhat weaker than last year. He said the Czech olayers are not able to top offensive play with good shooting and that it seemed to him they lacked a desire to win.HIStlt;Me lie Sn St iagvs St ItoiHIScTrD.ArTrinlt;SnWW.T1A;tomGi19mthre