He could also send many signals with a mirror. He usually used the mirror to warn someone of danger. Or he attempted to get the attention of a person far away. But he also used it to send messages in code. Of course, mirrors could be used only when the sun was shining. At night, Indians used fire arrows for signaling.

An Indian also sent signals with smoke. He made a small fire. Then he put grass or green branches on it. He held a blanket over the fire for a minute. When he removed the blanket from the fire, there was a cloud of smoke. The number of clouds of smoke told his message in code.

Now you can see that Indians didn’t need to learn each other's language. They could talk to one another by using signals or sign language.

31. From the passage we can infer that _________.

A. Indian language was difficult to learn, so many Indians never learned it

B. among the Indian tribes there was no common spoken language

C. many Indians couldn’t communicate with each other

D. Indians talked with each other only in two ways---sign and signal language

32. Which of the following statements is correct according to the passage?

A. One or two clouds of smoke sent different message.

B. In Indian sign language, “man’’ meant friend and “horse” meant enemy.

C. If an Indian rode his pony in a large circle, it meant there was danger.

D. Signals with smoke could be used to send messages at night.

33. What is the best title of this passage?

A. Indians’ way of life B. Each Indian tribe had its own language

C. How to use signals and sign language D. Talking without sound

B

People who are too happy die younger than those who are relatively unhappy, claims new research. A study which followed children from the 1920s to old age showed that people who were thought “highly cheerful” by teachers at school died younger than their classmates.

This was because people who were too happy were more likely to suffer from mental disorders, making them less fearful and more likely to take risks that increase the chance of having a deadly accident. Being too cheerful---especially at improper times---can also make others angry, increasing the risk of a person coming to harm.

Researchers from a variety of universities worldwide also discovered that trying too hard to be happy often ended up leaving people feeling more depressed than before, as putting an effort into improving their mood often left people feeling cheated.

And magazine articles offering tips on how to be happy were also blamed for worsening depression.

One study saw participants asked to read an article offering ways to improve your mood, and follow one of the tips to see how effective it was.

Participants then took the advice offered---such as watching a cheerful film---often concentrated too hard on trying to improve their mood rather than letting it lift naturally.

This meant that by the time the film had ended, they often felt angry and cheated by the advice given, putting them in a far worse mood than when they had started watching.

However, results of the study, published in the journal Perspectives on Psychological Science, proved that the key to true happiness was much simpler: meaningful relationships with friends and family members.

Study co-author Professor June Gruber, from the department of psychology at Yale University, said of people who actively tried to be happy: “When you’re doing it with the motivation or expectation that these things ought to make you happy, that can lead to disappointment and decreased happiness.”

“The true happiness is not money, or external recognition through success or fame. It’s having meaningful social relationships. ’’She added: “That means the best way to increase your happiness is to stop worrying about being happy and instead turn your energy to building the good