21. Each country, of course, in _______ Copenhagen has its own particular priorities and concerns, which is why ________ agreement is so difficult to reach.

 A. the; an        B. /; an       C. a; the         D. /; the

22. ---What on earth are the police busy with?

---They have been looking into how the plane crash _______.

 A. came out     B. came up      C. came down      D. came about