Which sentence structure correctly uses the subjunctive mood based on the original text's expression 'it is critical that...'?

A. it is critical that our nation bases policies

B. it is critical that our nation base policies

C. it is critical that our nation will base policies

D. it is critical that our nation based policies

核心考点：虚拟语气在重要性表达中的运用。解题思路：'it is critical that'后接should+动词原形，should可省略。选项分析：B选项'base'为原型动词正确；A/C/D分别错用单三/将来时/过去式。易错点提醒：注意美式英语常省略should，直接使用动词原形。

正确答案：B