A、By prediction. B、By recording. C、By observation. D、By examination. C文中提到两种方法，答案C是听到的原词，属于第一种方法。选项中的by说明此题考查一种做事方法。原文中有“自问自答”的地

Are you afraid to raise your hand in class, even when you know the answer? If you are, most people would say that you’re shy.
    If you feel shy, you’re not alone. Nine out of ten people are at least a little shy. But however shy you are, scientific evidence seems to show that it isn’t your fault. [16]You may have been born that way.
     [17]How do psychologists measure shyness? One way is by observation. They keep detailed records of people’s actions—like how often these people speak to others, or how long it takes someone to say hello to a stranger.
    Another way to measure shyness is to ask people questions. The test only takes about 10 minutes. It asks questions like "Do you like going out a lot?" and "Do you have many friends?" People must answer either yes or no. These questions can predict how people actually behave in social situations. Suppose the test tells you that someone is shy. Chances are good that a person will act shy.
    When scientists measure shyness, they’re really comparing degrees of shyness. In other words, when researchers say people are shy, they really mean they are shyer than others.
16. Why does the speaker say that it isn’t a fault to be shy?
17. What is one of the ways suggested by psychologists for measuring shyness?
18. What is the purpose of the psychologists in asking questions?