12. The main idea of the third paragraph (the highlighted portion) is that:
Your Answer is
Correct Answer is F
Explanation
The third paragraph mainly introduces that in the mid-nineteenth century, various new inventions made possible the development of modern private letters. L41-44 are paragraph topic sentences. Item F is in line with the intent of the paragraph.
Item G: It is just a detail and cannot serve as the main idea of the paragraph.
HJ item: There are no new inventions mentioned, but this paragraph focuses on introducing inventions.