Watt's steam engine soon showed what it could do. It liberated industry from dependence on running water. The engine eliminated water in the mines by driving efficient pumps, which made possible deeper and deeper mining. The ready availability of coal inspired William Murdoch during the 1790s to develop the first new form of nighttime illumination to be discovered in a millennium and a half. Coal gas rivaled smoky oil lamps and flickering candles, and early in the new century, well-to-do Londoners grew accustomed to gaslit houses and even streets. Iron manufacturers, which had starved for fuel while depending on charcoal, also benefited from ever-increasing supplies of coal: blast furnaces with steam-powered bellows turned out more iron and steel for the new machinery. Steam became the motive force of the Industrial Revolution as coal and iron ore were the raw materials.
(TPO6-Powering the Industrial Revolution)
Look at the four squares  that indicate where the following sentence could be added to the passage.
The factories did not have to go to the streams when power could come to the factories.
Where would the sentence best fit?
在上题中，“liberated industry from dependence on running water”和 “The factories did not have to go to the streams”句意便发生了重合。所以我们可以确定，文中第二句话的前后应该是我们可以选择的范围。
这个便是经常被大家忽略的地方。既然这句话，可以省略，那么这个插入句究竟要符合什么特点呢?还是以上题为例，我们发现 “liberated industry from dependence on running water”和 “The factories did not have to go to the streams”句意发生了重合，那究竟应该把插入句放在第二个还是第三个呢?这时就需要分情况讨论了：
在上题中，“liberated industry from dependence on running water”的意思是解放了工厂对水流的依赖。 “The factories did not have to go to the streams”的意思是工厂不用去往河流的位置。显然前者说的更概括和抽象，后者更具体，所以按照从大到小的顺序，应该选择第二个。
Trade between the West and the settled and prosperous Chinese dynasties introduced new forms and different technologies. One of the most far-reaching examples is the impact of the fine ninth-century AD. Chinese porcelain wares imported into the Arab world. So admired were these pieces that they encouraged the development of earthenware made in imitation of porcelain and instigated research into the method of their manufacture. From the Middle East the Chinese acquired a blue pigment—a purified form of cobalt oxide unobtainable at that time in China—that contained only a low level of manganese. Cobalt ores found in China have a high manganese content, which produces a more muted blue-gray color. In the seventeenth century, the trading activities of the Dutch East India Company resulted in vast quantities of decorated Chinese porcelain being brought to Europe, which stimulated and influenced the work of a wide variety of wares, notably Delft. The Chinese themselves adapted many specific vessel forms from the West, such as bottles with long spouts, and designed a range of decorative patterns especially for the European market.
Look at the four squares that indicate where the following sentence could be added to the passage.
Foreign trade was also responsible for certain innovations in coloring.
Where could the sentence best fit?
在上题中，我们发现，插入句的“certain innovations in coloring”与原文中的“the Chinese acquired a blue pigment”句意进行了重复，显然，插入句说的更概括，范围更大，所以根据从大到小的原则，应该选择第二个。