Over the course of the eighteenth century, the average output of ironwork tripled as a result of several improvements in blowing machinery and because coal replaced charcoal as the fuel used in the smelting of iron ore.
A.Over the course of the eighteenth century, the average output of ironwork tripled as a result of several improvements in blowing machinery and because coal replaced charcoal as the fuel used in the smelting of iron ore.
B.Over the course of the eighteenth century a tripling in the average output of ironwork was due to the replacement of charcoal by coal for the fuel used in the smelting of iron ore, in addition to several improvements in blowing machinery.
C.With charcoal’s being replaced by coal as the fuel used in the smelting of iron ore and several improvements in blowing machinery, the average output of ironwork tripled over the eighteenth century.
D.The replacement of charcoal with coal for the fuel used in the smelting of iron ore and several improvements in blowing machinery, the average output of ironwork tripled over the eighteenth century.
E.Charcoal being replaced by coal as the fuel used in the smelting of iron ore, and several improvements in blowing machinery, which tripled the average output of ironwork over the course of the eighteenth century.
不明白，答案选A。可是A明显不对称啊 作者: seyouji 时间: 2010-9-16 09:02
http://forum.chasedream.com/GMAT_SC/thread-341128-1-1.html作者: fenglikang 时间: 2010-9-16 09:07
GMAT里对称分两方面，一个是形式对称，一个是功能对称。这个题里主要体现的就是功能对称。原题里improvement和replacement是用and连接的，也就是说他们应该说并列关系。但是B选项里用了in addition to来连接这两个部分，这样就改变了原来的并列关系，也就是说改变了句子重心，所以是不对的啦~我一开始也选的B哦~~~14套开始是比较难啊，做的我灰常打击啊！楼主加油！作者: 绯雨白梅香 时间: 2010-9-16 09:15
Over the course of the eighteenth century, the average output 主语立刻补出了。B没有。 另外tripled 比tripling 好，无论coubled还是tripled，这样的用法就记住不要用tripling作者: zhaoyusee 时间: 2010-9-16 09:23