Americans eat vegetables per person today as they did in 1910.
A:more than twice
B:as twice as many
C:twice as many as
D:more than twice as many
西方近代民主制度的重要目标之一在于废除政治强制,遵守政治生活和公共生活中共同的规则,以宪法规定的方式获取政治资源。主要表现为胜者或暂时胜者一方将其形式化、法律化,固定为一种永久性的、历史性的进步。以下文献最能体现这一特点的是( )
下面关于生态系统功能的叙述不正确的是( )