单选题 Speaker A: ______?
Speaker B: I' m not sure. All I remember is that the flight number is 838.
A. Are we supposed to leave at 8:13 B. Are we suppose to leave at 8:13
C. Are we supposing to leave at 8:13 D. Are we supposed to be leaving at 8:13

【正确答案】 A
【答案解析】[解析] be supposed to do sth．表示“认为必须或应该做……”。