题目

Pirates from Somalia who hijacked _____European carrier in ______ Indian Ocean threatened to kill its 25 crew members if any rescue operation was attempted.    A. the; 不填             B. a; the               C. the; a                D.  the; the 答案：BThe math problem is really difficult for us_________.A. to work it out B. to work out C. to work out it D. working it out