You ______ so politely at the party. Everyone was casually dressed9/50Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. You ______ so politely at the party. Everyone was casually dressedmustn't have dressedneedn't have dressedcouldn't have dresseddidn't need to dressGiải thíchĐáp án B needn't have dressed: không cần làm gì nhưng vẫn làm