第2题: [单项选择]空气中一氧化碳浓度达()时具有爆炸性。 A. 13%-75% B. 13%-65% C. 20%-50% D. 5%-16% 参考答案:A
第3题: [单项选择]What is the most probable relationship between the woman and the man A. Saleswoman and customer, B. Mother and son. C. Professor and student. D. Manager and employee. 参考答案:C 答案解析:[听力原文] M: Sorry I did not come yesterday, because I had a fever. Could you tell me the requiremen