一束He-Ne激光从空气进入水中，则这束光传播速度变小，波长变小，因此颜色会发生变化。
查看答案
服务是一方能够向另一方提供的基本上是无形的任何行为或绩效，无形的任何________，并且不导致任何所有权的产生。
A. 有形产品
B. 活动或利益
C. 物质产品
D. 实体产品
What do these 28 units contain？
Actual interviews with experts.
B. Whole range of business and economic issues.
C. Key to all the exercises.
D. Warm-up and follow-up activities.
For whom is this book not suitable？
A. Those who are having a degree-level course.
B. Those who are on vocational training schemes.
C. Those who are on office professional training.
D. Those who are undertaking an English component.
听力原文：W: Does this train stop at the Beijing railway station？
M: There is a route map over there by the door.
Q: What does the man mean？
(4)
A. The woman should ask the person by the door.
B. The woman should get off immediately.
C. He will tell the woman when to get off.
D. The woman should check the map.
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