单项选择题

Decide which of the choices given below would best complete the passage if inserted in the corresponding blanks. Mark the best choice for each blank on your answer sheet.
More than 40 thousand readers told us what they looked for in close relationships, what they expected (31) friends, what they were willing to give in (32) , and how satisfied they were (33) the quality of their friendships. The (34) give little comfort to social critics. Friendship (35) to be a unique form of (36) bonding. Unlike marriage or the ties that (37) parents and children, it is not defined or regulated by (38) Unlike other social roles that we are expected to (39) as citizens, employees, members of professional societies and (40) organizations—it has its own principle, which is to promote (41) of warmth, trust, love, and affection (42) two people.
The survey on friendship appeared in the March (43) of Psychology Today. The findings (44) that issues of trust and betrayal are (45) to friendship. They also suggest that our readers do not (46) for friendship only among those who are (47) like them, but find many (48) differ in race, religion, and ethnic background. Arguably the most important (49) that emerges from the data, (50) , is not something that we found-but what we did not.