Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
Find the mistake: Of the most important machines (A) invented in the late nineteenth century, no machine (REMOVE) had a (OLD) great impact (EASY) on the USA’s economy than the automobile.
Answer C (great ⇒ greater)
Structure: comparative form + than
Among the most important machines invented in the late 19th century, none had a greater impact on the American economy than the automobile.