单选题 It is essential that applicants whose first language is not English ______ sufficient linguistic competence to avoid any delay or difficulty in pursuing their studies.
【正确答案】 C
【答案解析】句意：对第一语言为非英语的申请人来说，具备足够的语言学习能力对减少求学过程中的困难和滞后性至关重要。本题旨在考虚拟语气的用法。