错选b
B: Ron:you can't use 'that' in this sort of construction, because constructions using 'that of' (or other preposition after 'that') must have EXACTLY parallel structures. in other words, if the second half says 'that during 10,000 years', then the preceding half must say 'the growth of ___ during something else' (or some other time preposition, such as before or after, in place of during).
把倒装句看清楚。要注意，平行的对象并不是take care，provide，和milk。正常的语序为：
Provided with high-energy feed, and miked regularly, Holstein cows will produce an average of 2,275 gallons of mild each per year for the farmer who takes care to keep them cool。
A选项：本选项是一个系表结构，as a substitute for the telephone是Marconi’s conception of the radio的表语。在语法上，表语也称为主语的补语，在解释说明主语。因此，本选项的意思是：“M对于收音机的概念”是“电话的替代品”。但是，在逻辑上这是不正确的。因为，真正“是”电话的替代品的应该是“收音机”，而不是某人对收音机的概念，即，应该写为：
在习语上，begin to do和begin doing都是常见的，并且经常被认为相等。但其实，两者有明显的使用区别。begin doing一般是从第三方的角度描述doing这一事件，并不强调这件事的始发时间点，例如：
In 1990, Jack began playing the guitar.
该例句表明，杰克在1990年开始了弹吉他，不强调究竟是在1990年的哪个时间点开始弹的，只是一种客观的描述。又例如：
After scoring 760 in GMAT, Jack began to applicate his dream school.
该例句表明，在考了760分后，杰克开始申请他最想去的学校了，强调了在某个时间点后，杰克开始做申请这件事。
since it had been assumed that people lack sufficient free time to maintain current television-viewing levels while spending increasing amounts of free time on the computer. 关键句
free time and spending increasing amounts of free time on the computer-》b不对
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句中pefer to排除CDE（注意仔细看句中可能考点而不是根据前两个词就排除）
B中that修饰machines,错误“machines, that”