常用折射率：水（）、钻石（）、玻璃（）、空气（）、冰（）。
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（）贴图是具有光源信息的图片，Keyshot能利用这些图片来充当光源。
Directions: Watch the video and choose the best answer accordingly.1. Which statement is not mentioned?
A. The 21st century sees an increasingly connected world owing to the Internet and other infrastructure.
B. The concept of global village is now a reality.
C. The world is a totally peaceful place.
D. China's solution to global challenges is the proposal of a community with shared future for mankind.
In the Belt and Road Iniatiative, the Belt refers to the ______ belt along the Silk Road .
A. economic
B. geographic
C. traffic
D. cultural
In the Belt and Road Iniative, the Road refers to ______.
A. the ancient Silk Road
B. the ancient maritime Silk Road
C. the Silk Road for the 21st century
D. the Maritime Silk Road for the 21st century
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