Complete the sentences with prepositions. Look at the text to help you.
1. Astronauts must have a lot .................their minds when they prepare to go into space.
2. Look............... that starry sky. Isn't it beautiful?
3. Many scientists think we may be able to live............. other planets.
4. If we compare the air on Mars.................... that on Earth, we find very few similarities.
5. The astronauts didn't find any signs...................... life on the moon.
6. Modern spacecraft are very different...................... earlier spacecraft.