[originaltext] The secret of a long and happy marriage appears to be not to

The secret of a long and happy marriage appears to be not to expect too much from it. Far better, US researchers say, to aim low to ensure you are not disappointed. [16]The key to keeping that newlywed glow appears to be forgiveness and communication. [17]The study by researchers from Ohio and Florida Universities looked at 82 couples. They quizzed all the spouses independently over four years.
    Writing in the Journal of Personality and Social Psychology, researchers led by James McNulty, professor of psychology at Ohio University, said: "In contrast to the idea that expectations in the early years of marriage exert main effects on satisfaction, [18]the current findings suggest that the effects of expectations interact with the skills partners bring to their relationships." The study also found that people tend to select like-minded partners who they believe will be able to maintain a stable relationship. The finding contradicts the old belief that opposites attract. Instead, the US researchers said people looking for long-term relationships should select partners who were similar to themselves, rather than seeking out the highest quality partner available.
16. What is the key to a happy marriage according to the study?
17. How many people are investigated in the study?
18. Which is the belief of the researchers?