关于方差最小化法，说法正确的是（）。
Ⅰ债券组合收益与指数收益之间的偏差称为追随误差
Ⅱ求得追随误差方差最小化的债券组合
Ⅲ适用债券数目较大的情况
Ⅳ要求采用大量的历史数据
Thetwinshadbeenawayforsuchalongtimethatmanypeopleinthevillagethoughtthey________.
InGoDown,Moses,()illuminatestheproblemofblackandwhiteinSouthernsocietyasacloseknitdestinyofbloodbrotherhood.
preferred,prefers,is,are,was,were,willbe,shallbeDuringtheholidayweek,one-thirdofthestudentsinourclass________preparedtostayoncampusforstudywhilearoundtenpercentofthem________somemoresleepathome.
Lyingundertheskull,thehumanbraincontainsanaverageoftenbillionnervecellscalled______.
Ifyouarewalkingawayfromaclocktower，youwillhearthetickingoftheclockfadetoapoint________itcannotbeheard.