By far , the largest of the three major sections of the United States is the area between the Appala

By far , the largest of the three major sections of the United States is the area between the Appalachians and the Rocky Mountains. ( ) A. Up to now B. On the whole C. To a great degree D. In general

The phrase "by far" in the sentence emphasizes a significant degree of superiority or difference. According to the provided references, "by far" means "by a considerable margin" or "to a great extent" when comparing something as the most significant or dominant among alternatives . It is not simply about time ("up to now") or general overview ("on the whole"/"in general"), but rather emphasizes a clear and substantial advantage.

For example, in "This book is by far the best," "by far" strengthens that the book is significantly better than others . Similarly, the original sentence highlights that the region between the Appalachians and Rockies is not just large, but overwhelmingly the largest among the three major sections of the US.

The correct answer is C. To a great degree, as it captures the core meaning of "by far" as emphasizing a substantial difference or superiority . While "up to now" (A) refers to time , and "on the whole"/"in general" (B/D) describe overall trends, none convey the critical sense of significant comparative advantage that "by far" requires.

Does this explanation clarify how "by far" functions differently from common time or summary adverbs?