【题目】The students are holding a heated discussion about what clothes are______for school wear.
A.formal
B.appropriate
C.correct
D.appreciate

【答案】B
【解析】A. formal正式的；B. appropriate合适的；C. correct正确的；D. appreciate欣赏，感激。句意：同学们正在热烈讨论是否有必要穿校服。根据句意可知选B。