第三节 语法和词汇知识(共15小题；每小题1分，满分15分)
11.（2012·开封模拟）At _______ recent sports science conference, hundreds of participants discussed _______ benefit of barefoot walking.
A. the；a B. a; the C. 不填；the D. the; 不填
12. （2012·南昌模拟）You had better not discuss the problem at the meeting. You may discuss it _______ tea.
A. in B. at C. for D. over
13.（2012·太原模拟）_______ our team seems to lack at the moment is the determination to win the match.
A. That B. What C. Whether D. If
14. —Jenny has failed to seek advice from Professor Li on the problem again.
—What a shame! If only she _______ before he went abroad on business.
