💡 Detailed Explanation
The grammar pattern '〜わけにはいかない' expresses that one cannot do something due to social norms, common sense, or personal circumstances. To form the sentence 'Under these circumstances, we can't possibly proceed with the plan as it is,' the correct order is 「計画を」「このまま」「進める」「わけには」. The word that goes in the star (★) position is the third one, 「進める」.