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【单选题】
锅炉停用时间超过一个月,应该 。A.
停火留汽
B.
熄炉,用碱度适合的水保持正常水位
C.
采用保养法
D.
用干燥保养法
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【简答题】流星进入地球大气层时，由于与大气发生剧烈摩擦，会使流星燃烧发光．小明问老师：“发射火箭时，火箭同样也与空气发生剧烈摩擦，为什么没有燃烧发光？”老师解释说：“科学家们一方面研制了可耐几千摄氏度的耐高温材料；另一方面还在火箭头部涂了一层特殊材料，这种材料在高温下熔化并汽化，能起到防止烧坏火箭的作用．”请回答涂这层特殊材料为什么能起到防止烧坏火箭头部的作用？
【简答题】Gia đinh anh có ______ ai nhỉ?
【单选题】听力原文：M: Susan, I would like to introduce a friend of mine, if I may, Tim Bums. W: Pleased to meet you, Mr. Tim Burns. Q: What's the relationship between Susan and Tim Burns? (4)
A.
Have met for several time.
B.
Classmates.
C.
Don't know each other before.
D.
Friends.
【单选题】听力原文：W: If you have a few minutes, I'd like to talk with you about my project. M: Please go on. Q: What does the man mean? (17)
A.
He prefers to talk another time.
B.
He wants the woman to go away.
C.
He would like the woman to continue.
D.
He doesn't know what to think.
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