21. --- Has ______ English changed over time?
   --- “No”, he answered without ______ second thought.
   A. /; the      B. /; a       C. the; the      D. the; a 
22. If my brother doesn’t go camping, _______.
A. so will I       B. so do I       C. neither will I       D. neither do I
23. Iraq has _______ too many wars since 1990s, making his people suffer a lot.
A. gone through       B. looked through      C. got through      D. passed through