阅读理解

The American frontier is sharply distinguished from the European frontier -- a fortified boundary line running through dense populations. The most significant thing about the American frontier is, that it lies at the hither edge of free land. In the census reports it is treated as the margin of that settlement which has a density of two or more to the square mile. The term is an elastic one, and for our purposes does not need sharp definition. We shall consider the whole frontier belt, including the Indian country and the outer margin of the "settled area"of the census reports. This paper will make no attempt to treat the subject exhaustively; its aim is simply to call attention to the frontier as a fertile field for investigation, and to suggest some of the problems which arise in connection with it.

It can be inferred that the phrase "elastic one" suggests which of the following? Select all correct choices.
A.The American frontier's boundaries are more fluid than static
B.The ways in which we define the American frontier differ and are multifarious
C.The American frontier can be defined in very specific and distinct terms

We can infer that the larger essay from which the passage is take focuses mainly on
A.The differences between the American frontier and the European frontier
B.The European settlements on the American frontier
C.The positive and negative effects of the American frontier
D.The importance of census reports
E.The fluctuation of population groups on the American frontier

参考答案

1.正确的答案：A B

2.正确的答案：C