Summarization：the paragraph is followed by an incomplete phrase or sentence which summarizes the main idea of the paragraph. Spell out the missing letter of the word on your answer sheet.

Common interests appear to be a significant factor in selecting friends. Very close and trusted friends share faith in each other. They feel secure that they will not be ridiculed, and their faith will be respected. Betraying a trust is a very quick and painful way to terminate a friendship.
Common faith helps k friendship.