21.It is said that _____ good companion is better than _____ fortune, which can’t buy true qualities.

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

22.The silence of the library is sometimes broken by a sudden cough or the sound of pages _____.

 A. turning            B. turned           C. being turned          D. having turned

23.A number of people suffer ill effects from drugs ______ they take the drug exactly as directed.

A. even though         B. as if            C. in case               D. in that

24.No important progress was made in the UN Climate Conference in Copenhagen as ______ of the rich countries agreed to offer large amounts of money to fight global warming.

 A. nothing            B. none            C. neither               D. both