题目内容：

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It is said that all dreams serve a purpose（目的）. While there is no agreement among scientists about why we dream, there are many ideas about the different kinds of dreams we have.

One common kind of dream is the repeating dream, in which the same story is repeated again and again, often for many months or even years. Some believe these are a sign people have a problem in their life and once that problem is gone then the dream will stop. Others think they are a way to help people remember something very important.

Another well-known kind of dream is the nightmare. The pictures and stories in such dreams make people very afraid and dreamers usually remember them far more clearly than normal dreams. The cause of such dreams may be seeing something terrifying such as a car accident or some deadly snakes. Others think such dreams may be trying to make a person pay attention to something that is dangerous in their life.

Daydreams happen during wake-time when we forget where we are or what we are doing and find ourselves in a made-up story or unreal world. We often daydream when we are doing something that is not interesting or exciting. They help us think about our future.

Lucid dreams are the most fun. These happen when dreamers suddenly understand that they are dreaming. Instead of waking up, they stay in the dream and are able to control what happens in the dream as if they are making a movie.

1.The underlined word “they” (in paragraph 2) refers to “_________”.

A．dreams

B．problems

C．dream

D．scientists

2.The underline word “terrifying” (in paragraph 3) is closest in meaning to _________.

A．frightening

B．interesting

C．disappointing

D．amazing

3.When might a person daydream?

A．During a very interesting movie.

B．While playing at a fun park.

C．While listening to an uninteresting talk.

D．When making a movie.

4.How do we know if we are lucid dreaming?

A．We can remember the dream very clearly.

B．We can control what happens in the dream.

C．We think that the dream is like a movie.

D．We feel very nervous after we wake up.

5.What is the best title of the passage?

A．Daydream of You

B．Enjoy Your Dream

C．What Dreams Mean

D．Where Dreams Go