We've landed on the moon and sent spacecraft to Mars.But how would you like to take a walk around the red planet itself，having a closer look at the rocky Marian surface from all angles？Well，for those who can't afford a rocket ship，experiences like this are now a "virtual" step closer，thanks to AR（Augmented Reality） technology.
AR refers to the process of displaying digital information on top of the physical world using an electronic device.The device could be a pair of smart glasses，a tablet or even a smart phone.
Unlike "virtual reality"，or VR，users can touch objects and move around in this digital world，instead of being restricted to a small area.This is particularly exciting for businesses.
These days，it's possible to virtually try on or try out a variety of goods before buying via AR apps：Sephora's app lets you view cosmetics（化妝品） in AR on your face；QUANU offers a chance to "see" furniture in your home；paint brands let you virtually view colors on your walls.These offerings provide a way to enhance in-store experiences or make life much easier for busy shoppers.
In time，AR advocates hope it will allow us to interact with a whole world that is enhanced by multimedia provided by very clever computers- transforming not only business，but also fields like healthcare，manufacturing，telecommunications，education，and public safety.A doctor could see patients around the world from the comfort of his own home.
Not everyone is convinced that either the technology or the world is ready.Kipman，the creator of the HoloLens，thinks we still have a long way to go before AR reaches its potential. "We will look back at this decade as being like cavemen in terms of technology，" he said.
（1）What is the main feature of AR？
C
C
A．Users may be limited to a fixed position.
B．It can be operated on any electronic device.
C．Users can physically explore the digital world.
D．It separates digital information from the physical world.
（2）What can we learn from the examples in the third paragraph？
B
B
A．AR provides high-quality goods.
B．AR enhances consumer experiences.
C．AR enjoys enormous popularity.
D．AR boosts economic development.
（3）What is Alex Kipman's attitude towards AR？
A
A
A．Cautious.
B．Intolerant.
C．Doubtful.
D．Critical.
（4）What can we infer from the passage？
D
D
A．AR has taken the place of VR.
B．AR is widely used in health care.
C．The world is well prepared for AR.
D．AR has a relatively bright prospect.
