51. Nobody but Jane ________ the secret.
A. know B. knows C. have known D. is known
【解析】主谓一致。but, with等连接两个名词或代词作主语时，谓语动词应与but, with前面的名词或代词保持一致。由此可知，谓语动词应与Nobody保持一致，Nobody为不定代词，作主语时，谓语动词通常用单数形式。另外，本句是在陈述客观事实，所以应用一般现在时。故选B。
52. A famous writer’s new book My New Life will ________ next month.
A. come across B. come out C. come along D. come about
【解析】词义辨析。come across偶遇，无意中发现;come out出版，发表;come along出现，跟着来，进步;come about发生，产生。根据句意可知，选B。
53. —How many left-behind children are there in your class?
A. Nothing B. Nobody C. Neither D. None
【解析】词义辨析。nothing：没什么，没事，没有东西;nobody：无人，没有任何人，不强调数量，可用来回答who引导的问句;neither：两者都不;none：没有人，一个也没有，既可指人又可指物，强调数量，可用来回答how many/how much引导的问句。根据句意可知，此处强调数量，所以应用none来回答。故选D。
54. Since nobody gave him any help, he ________ have done the research on his own.
A. can B. must C. would D. need
【解析】情态动词。can have done和need have done主要用于否定句和疑问句中;must have done表示对过去情况的肯定推测，意为"一定已经做了某事";would have done表示与过去事实相反的假设。根据句意可知，此处表示的是对过去情况的肯定推测，所以应用must have done。故选B。
55. In the last few years, thousands of films ________ all over the world.
A. have produced B. have been produced
C. are producing D. are being produced
【解析】动词时态和语态。根据句意和时间状语In the last few years可知，本句应用现在完成时，表示动作从过去某个时间开始，延续到现在，并仍然可能延续下去。另外，films和 produce之间为逻辑上的动宾关系，所以应用被动语态。故选B。
