题目

Nokia, the world's largest mobile phone maker, said that over the first nine months of the year it _____ 23 million handsets in China, an increase of 77 percent _____ the same period a year ago.  A. sold; comparing with           B. has sold; compared to C. had sold; compared to             D. was selling; compared with   答案：C  考查短语及动词时态。根据句意say用一般过去时，则sell需用过去完成时，表示过去已经销售；compared to与......相比。  下列关于模拟信号与数字信号的说法正确的是（　　）A．模拟信号比数字信号的抗干扰能力强B．模拟信号比数字信号的抗干扰能力差C．模拟信号与数字信号的抗干扰能力一样好D．电话只能用数字信号传输信息