A、They expand our mind. B、They prolong our lives. C、They narrow our focus. D、They lessen our burdens. A讲座中提到，积极情绪能通过提高我们的感悟能力、注意

Let’s say you start to brainstorm a list of all the emotions you’ve ever experienced. Just for fun, try it now.
    What’s on your list? Chances are, you included things like happy, sad, excited, angry, afraid, grateful, proud, scared, confused, stressed, relaxed and amazed. Now sort your list into two categories—positive emotions and negative emotions.
     (16)Feeling both positive and negative emotions is a natural part of being human. We might use the word "negative" to describe more difficult emotions, but it doesn’t mean those emotions are bad or we shouldn’t have them. Still, most people would probably rather feel a positive emotion than a negative one. It’s likely you’d prefer to feel happy instead of sad, or confident instead of insecure.
    What matters is how our emotions are balanced—how much of each type of emotion, positive or negative, we experience.
    Negative emotions warn us of threats or challenges that we may need to deal with. For example, fear can alert us to possible danger. It’s a signal that we might need to protect ourselves. Angry feelings warn us that someone is stepping on our toes, crossing a boundary, or violating our trust. Anger can be a signal that we might need to act on our own behalf.
    Negative emotions focus our awareness. They help us to zero in on a problem so we can deal with it.(17)But too many negative emotions can make us feel overwhelmed, anxious, exhausted or stressed out. When negative emotions are out of balance, problems might seem too big to handle.
    The more we dwell on negative emotions, the more negative we begin to feel. Focusing on negativity just keeps it going. Positive emotions balance out negative ones, but they have other powerful benefits, too.
    Instead of narrowing our focus like negative emotions do,(18)positive emotions affect our brains in ways that increase our awareness, attention and memory. They help us take in more information, hold several ideas in mind at once, and understand how different ideas relate to each other. When positive emotions open us up to new possibilities, we are more able to learn and build on our skills. That leads to doing better on tasks and tests.
    People who have plenty of positive emotions in their everyday lives tend to be happier, healthier, learn better, and get along well with others.
Questions 16 to 18 are based on the recording you have just heard.
16. What does the speaker say about negative emotions?
17. What happens to people whose negative emotions are out of balance?
18. How do positive emotions affect us?