1. Scientists claim that the discovery of the first authenticated mammal bones in amber could provide important clues of determining, in addition to how, when mammals colonized the islands of the West Indies.
A of determining, in addition to how, when mammals colonized the islands of the West Indies
B in the determination of how and when the islands of the West Indies were colonized by mammals
C to determine how mammals colonized the islands of the West Indies and when they did
D for determining when the islands of the West Indies were colonized by mammals and how they were
E for determining how and when mammals colonized the islands of the West Indies
答案E, 我是看了 provide ... to, 就把E排除了呢, 这题有点晕....
20. In the 1820’s, anthracite coalfields opened in eastern Pennsylvania, and when canals and eventually railroads reached into the region, there were substantial supplies of coal that was exported to the nation’s growing mills, forges, factories, and railways.
A when canals and eventually railroads reached into the region, there were substantial supplies of coal that was
B (排除)
C (排除)
D (排除)
E as canals and eventually railroads reached into the region, substantial supplies of coal were
答案A, 那么E 怎么不好呢?
谢谢NN
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