In 1914 a total of 469,000 cars and trucks were produced in the United States, but in 1929 almost twice the numbers of trucks alone came off the assembly lines. A. the numbers of trucks alone B. that number of trucks alone C. the number of trucks by themselves D. as many trucks themselves E. as many trucks by themselves
ChaseDream GMATPrep2008 语法笔记 V 2.00 http://forum.chasedream.com/GMAT_SC/thread-484446-1-1.html  184页有 摘取如下: Number的用法:a number of(大量的),the number of(……的数量),numbers of (许多)。详见新prep1-209(笔记P43) A. the numbers错误,twice后面要跟单数的number,即twice the number;但是改为the number后,指代特定的数字还是用that number更为明确 B. Correct;came off作过去分词修饰trucks;that number指代前面总和的469000,如果是the number,没有指代对象,似乎说是the number of trucks