单项选择题
A．it is large B．it is very small C．it takes little time for a computer to read D．it is the size of a short note
A．someone who breaks into and uses someone else's computer B．someone who breaks commercials C．someone who fixes someone else's computer D．someone who does not know about computers
A．made by the hackers and put on computers B．not found by the experts C．prepackaged and found on many computers D．hard to find