题目

New computers are soon out of date since newer models are ________ constantly. A．turned up                         B．turned out C．turned down                       D．turned over 答案：B 句意：由于更新型的电脑不断地被生产出来，新电脑也很快就过时了。此题考查动词词组。turn up“出现”，不能用在被动语态中；turn out“生产，制造出来”；turn down“拒绝”；turn over“翻身，翻转”。故选B。下列各数0，π，，，，，0.121121112…（每两个2之间依次多一个1）中无理数的个数为A.4B.3C.2D.1