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【单选题】
Section A Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A, B, C and D, and decide which is the best answer. 听力原文：M: No mail for me today? They must have forgotten about me. I hope everything is all right at home. W: No news is good news. Remember many things am slow these days. Q: What can we learn from the conversation? (12)A.
No news is good news.
B.
The woman works in the post office.
C.
The man's family forgot him.
D.
The man expects to hear from his family.
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【简答题】已知流速场 ，求空间点M(3，0，2)在t=1时的加速度。
【单选题】最高运行速度不超过（）的列车，机车信号设备与列车运行监控记录装置结合使用，或采用列车超速防护系统。
A.
120km/h
B.
140km/h
C.
160km/h
D.
200km/h
【单选题】已知空间两个动点A（m，1+m，2+m），B（1-m，3-2m，3m），则| AB |的最小值是（ ）
A.
7 19
B.
3 17
C.
3 17 17
D.
9 17 17
【单选题】已知空间三点 M (1,1,1) 、 A (2,2,1) 和 B ( 2 , 1 , 2 ),求 ∠ AMB 是
A.
pi/2
B.
pi/4
C.
pi/3
D.
pi