单选题   The human brain contains 10 thousand million cells and each of these may have a thousand connections. Such enormous numbers used to discourage us and cause us to dismiss the possibility of making a machine with human-like ability, but now that we have grown used to moving forward at such a pace we can be less sure. Quite soon, in only 10 or 20 years perhaps, we will be able to assemble a machine as complex as the human brain, and if we can we will. It may then take us a long time to render it intelligent by loading in the right software(软件)or by altering the architecture but that too will happen.
    I think it certain that in decades, not centuries, machines of silicon(硅)will arise first to rival and then exceed their human ancestors. Once they exceed us they will be capable of their own de-sign. In a real sense they will be able to reproduce themselves. Silicon will have ended carbon's long control. And we will no longer be able to claim ourselves to be the finest intelligence in the known universe.
    As the intelligence of robots increases to match that of humans and as their cost declines through economies of scale we may use them to expand our frontiers, first on earth through their ability to withstand environments. harmful to ourselves. Thus, deserts may bloom and the ocean beds be mined. Further ahead, by a combination of the great wealth this new age will bring and the techno-logy it will provide, the construction of a vast, man-created world in space, home to thousands of millions of people, will be within our power.

单选题     In what way can we make a machine intelligent?

单选题     What does the writer think about machines with human-like ability?

单选题     The word carbon(Line 3, Para.2)stands for '______'.

单选题     A robot can be used to expand our frontiers when ______.

单选题     It can be inferred from the passage that ______.