城乡一体化是我国现代化和城市化发展的一个新阶段。A. Urban-rural integration is an old stage in China's development toward modernization and urbanization.B. Urban-rural integration is a new stage in China's development toward modernization and urbanization.C. Urban-rural integration is a new stage in China's development toward industrialization and deurbanization.D. City-countryside unification is a new stage in China's development toward modernization and urbanization.

本题考查对中文句子的英文翻译理解，解题思路是是将中文句子逐词分析，再与各个英文选项进行细致比对。

• 首先分析中文句子“城乡一体化是我国现代化和城市化发展的一个新阶段”。
  • “城乡一体化”常见的英文表达为“Urban - rural integration” ，“City - countryside unification”虽然也有“城乡统一”的意思，但“一体化”用“integration”更能准确表达原句含义。
  • “我国现代化和城市化发展”对应的英文是“China's development toward modernization and urbanization” 。
  • “一个新阶段”即“a new stage”。
• 接着看选项：
  • A选项中“an old stage”与原句“一个新阶段”不符，所以A错误。
  • B“Urban - rural integration is a new stage in China's development toward modernization and urbanization”，与我们分析的英文表达一致，所以B正确。
  • C中“industrialization and deurbanization”与原句“现代化和城市化”不符，所以C错误。
  • D中“City - countryside unification”不如“统一”与“一体化”意思有偏差，所以D错误。