These two materials are essential to so much of our infrastructure and technology, and they have a complementary set of strengths and weaknesses.

这两种材料对于基础设施和科学技术都很重要，并且他们有互补的优点和缺点。

Parsons’ theory was that a successful family needs people to have complementary skill sets, and gender gives us a way of pairing off these skills.

帕森斯的理论是，一个成功的家庭需要人们拥有互补的技能，而性别为我们提供了一种将这些技能配对的方式。