21. Seldom are the superstitious practices recorded ______ present practical theories ______ modern psychology relates.

A. which, to which               B. that, which                      C. what, to which                 D. /,/

22. ______, they seemed not a bit unconfident while giving a speech.

A. Although they wee not a bit ill-prepared                       B. As they were not a little ill-prepared

C. Well-prepared as they were                                         D. I’ll-prepared though they were

23. Rainfall is moderate over most areas of America, rivers and underground water permit extensive irrigation ______ it is not.

A. when                              B. if                                    C. where                             D. that

24. Sherlock Holmes was born a detective, ______ quite a few cases ______ his keen observation and natural instinct for human nature.

A. which, was based on         B. whose, based on               C. though, was based on        D. with, based on

25. Whether or not Carlyle’s theory ______ true is debatable, ______ certain individual cast long shadows is not.

A. proves, but that                B. is proved, but                  C. proves, but                      D. is proved, but that