21. （2011河北承德联校高三上学期期末联考）—Excuse me, Professor Smith, I was wondering if I could leave a quarter earlier today.
—________.
A. Nothing the matter B. Sure, go ahead
C. Oh, why not? D. Of course, no problem
22. （山东师大附中2008级打靶考试）I didn’ t make sense of ____ poem until I read it ____ third time.
A. the; the B. a; the C. the; a D. a; a
