美国官员：加拿大在谈判中没有展现出与墨西哥同等的建设性。

Group 1 - The core viewpoint of the article indicates that U.S. officials believe Canada has not demonstrated the same level of constructiveness in negotiations as Mexico has [1] Group 2 - The article highlights the ongoing negotiations involving Canada and Mexico, suggesting a disparity in their approaches [1] - U.S. officials' comments imply a need for Canada to enhance its negotiation strategy to align more closely with Mexico's [1]