OG8 阅读 Q33

Choice C is the best answer. In the second paragraph of Passage 1, Douglas uses a rhetorical question to stress that the division into slave and free states has existed since the beginning of the United States: "I now come back to the question, why cannot this Union exist forever, divided into Free and Slave States, as our fathers made it?" It can be inferred from this question that Douglas believes that since this division is long-standing, the provisions for it in the US Constitution have provided a good basic structure that doesn't need to be changed.
Choice A is incorrect because in Passage 1, Douglas doesn't observe that the US Constitution's provisions for slavery lack a means for reconciling differences between slave states and free states. Choice B is incorrect because although Douglas stresses that the provisions for slavery are long-standing, he doesn't characterize them as having somehow anticipated the Union's expansion to the west. Choice D is correct because although it can be inferred from Passage 1 that Douglas believes the provisions for slavery have had a positive economic impact, he nowhere implies that the founders based them on an assumption that slavery was economically necessary.