How much do you know about our�
�����������������������Solar System?��������������������������������������������������������������������������������
�
�I.��Look at�the pictures and write the proper vocabulary.
�
�
�II. Choose the right option.
Our planet, Earth, is the �planet from the sun. Earth orbits the �once every year, or �days.
Earth has one . It is about 385,000 km from Earth. It orbits the Earth �days. Our closest neighbors are the planets .
�
III. Choose the�proper form of the verbs.
For hundreds of years, people , "Is Mars 
like our planet? �life on Mars? Or��life in the past?�����������
�
Life on Earth �water to exist.��
� So, scientists �asking, �water on��Mars?��������������������������
In 2004, NASA �two robot explorers 
or rovers� to Mars. Their mission? To find signs of water.����
�
The rovers��seven months to fly to Mars.�
Since 2004, the rovers �back a lot of information.
�
Who �what the next rovers ?
�
Scientists � that Mars was warmer many years ago.
There �to be rivers and seas on Mars.
A hundred years from now, maybe humans living� 
on Mars �oxygen equipment to breath.���������������
�
IV. Correct the verb tenses in yellow.
1. Right now, a team of astronauts live �350 km above Earth in a spacecraft called International Space Station.�
2. Astronauts used to eat mashed food from tubes, but scientsists discovered �better ways to cook in space.
3. Every day, ISS�Astronauts�have worked��very hard. They do science experiments, build the space station or exercise.
4. When Bill Shepherd have �free time, he liked to e-mail people at home and watch movies.
5. In the future, it cost �the united States and other countries billions of dollars to participate in the ISS.
6. Muscles and bones�becomes��weak in space. Some scientists believe that humans�live��in space some day, so astronauts is studying �other changes that happen to the human body during long periods in low gravity.�
�
