题目内容：
根据下列文章,请回答题。Controlling Robots with the Mind
Belle, our tiny monkey, was seated in her special chair inside A cha mber at our Duke University lab. Her right hand grasped a joystick (操纵杆) as she watched A horizontal series of lights on adisplay panel. She knew that if alight suddenly sho, ne and she moved the joystick left or right to correspond to its position, she would be sent adrop of fruit juice into her mouth.
Belle wore A cap glued to her head. Under it were four plastic connectors, which fed arrays of microwires - each wire finer than the finest sewing thread- into different regions of Belle's motor cortex, the brain tissue that plans movements and sends instructions. Each of the 100 microwires lay beside A single motor neuron (神经元) When aneuron produced an electrical discharge, the adjacent microwire would capture the current and send it up through asmall wiring bundle that ran from Belle's cap to A box of electronics on A table next to the booth. The box, in turn, was linked to two computers, one next door and the other half acountry a way.
After months of hard work, we were about to test the ide athat we could reliably translate the ra w electrical activity in aliving being's brain - Belle's mere thoughts - into signals that could direct the actions of arobot. We had assembled a multi jointed robot arm in this room, a way from Belle's view, which she would control for the first time. As soon as Belle's brain sensed alit spot on the panel, electronics in the box running two real-time mathematical models would rapidly analyze the tiny action potentials produced by her brain cells. Our lab computer would convert the electrical patterns into instructions that would direct the robot arm。 Six hundred miles north, in Ca mbridge, Mass, adifferent computer would produce the sa me actions in another robot arm built by Mandaya m A. Srinivasan, If we had done everything correctly, the two robot arms would beha ve as Belle's arm did, at exactly the sa me time.
Finally the moment ca me. We randomly switched on lights in front of Belle, and she immediately moved her joystick back and forth to correspond to them. Our robot arm moved similarly to Belle's real arm. So did Srinivasan's. Belle and the robots moved in synchrony (同步), like dancers choreographed (设计舞蹈动作) by the electrical impulses sparking in Belle's mind.
In the two years since that day, our labs and several others ha ve advanced neuroscience, computer science and microelectronics to create ways for rats, monkeys and eventually humans to control mechanical and electronic machines purely by"thinking through," or ima gining, the motions. Our immediate goal is to help A person who has been unable to move by A neurological (神经的) disorder or spinal cord (脊髓) injury,but whose motor cortex is spared, to operate A wheelchair or A robotic limb.
Belle would be fed some fruit juice if she
A．grasped the joystick.
B．moved the joystick to the si
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