1. 阅读短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。

The seasons on Earth

    The Earth that we live on is moving all the time. The Earth turns around itself once every 24 hours. This gives us day and night. The Earth also travels around the Sun once every year. This gives us the four seasons. We have spring and summer when our part of the Earth leans (倾斜) towards the Sun. We have autumn and winter when our part of the Earth leans away from the Sun.

    In many places on Earth, there are four seasons in a year. But in some places there are only two seasons. For example, near the North Pole (北极) there are only winter and summer. The winter nights are long. For more than two months you can't see the Sun, even at noon. The summer days are long. For more than two months the Sun never sets, and there is no night. In the tropics (热带地区) there are also two seasons: a rainy season (wet season) and a dry season.

1. （1） It takes the Earth ________ to turn around itself once.

   A . a day B . a week C . a month D . a year
3. （2） We have ________ because the Earth travels around the Sun.

   A . 24 hours B . day and night C . one week D . four seasons
5. （3） When our part of the Earth leans away from the Sun, we have ________.

   A . winter and spring B . spring and summer C . summer and autumn D . autumn and winter
7. （4） There is/are only ________ in the tropics.

   A . spring and summer B . autumn and winter C . a wet season and a dry season D . a rainy season and a wet season