如果变量x、y的相关系数为0，则表示（）。A.二者没有相关关系  B.二者存在高度相

北京、沈阳等七城市的调查显示，股票在居民选择的投资形式中占有最高比例，下列对股票的认识正确的有 [ ] 

A．股票是有限责任公司发给股东的入股凭证

B．股票是股份有限公司发给股东的入股凭证，是股东取得股息的一种有价证券

C．拥有股票的人就是股份公司的董事

D．股票是企业筹集资金的唯一方式

(二) For any Englishman, there can never be any discussion as to who is the world’s greatest dramatist. Only one name can possibly suggest itself to him : that of William Shakespeare. Every Englishman has some knowledge, however slight, of the work of the greatest writer. All of us use words, phrases and quotations from Shakespeare’ s writings that have become part of the common property of theEnglish - speaking people. Most of the time we are probably unaware of the source of the words we used, rather like the old lady who was taken to see a performance of Hamlet and complained that it was full of wellknown proverbs and quotations. Shakespeare, more perhaps than any other writer, makes full use of the great resources of the English language. Most of us use about five thousand words in our normal use of English; Shakespeare in his works used about twentyfive thousand. There is probably no better way for a foreigner to appreciate the richness and variety of the English language than by studying the various ways in which Shakespeare used it. Such study is well worth the effort (it is not, of course, recommended to beginners) even though some aspects of English usage, and the meaning of many words, have changed since Shakespeare’ s day.

What does the word "proverb" mean ？______

A．Familiar sayings

B．Shakespeare’s plays

C．Complaints

D．Well-known phrases

1845年在中国出现的第一家新式银行是().

A.横滨银行

B.东方汇理银行

C.汇丰银行

D.丽如银行

装置需要扬程

B细胞的阴性选择发生于（）

A.早期祖B细胞

B.晚期祖B细胞

C.不成熟B细胞

D.成熟B细胞

E.浆细胞