55.
Your Answer is
Correct Answer is C
Explanation
Pilots is the subject of the next sentence, and there are complete sentences before and after the underlined part, so C is correct. to date fixed collocation, "so far".
55.
Your Answer is
Correct Answer is C
Explanation
Pilots is the subject of the next sentence, and there are complete sentences before and after the underlined part, so C is correct. to date fixed collocation, "so far".