安全困境是国际政治的一个基本特征,因为国家增加自身安全的努力往往会降低其他国家的安全。
The security dilemma is a fundamental feature of international politics, as states' efforts to increase their own security often decrease the security of others.
Urban forestry proves that nature and cities can thrive together.
要解决问题,你必须愿意以不同的方式思考。