Complete each sentence so that it means the same as the first sentence

Complete each sentence so that it means the same as the first sentence.

1. 
   Learning how to live in space is difficult.
   

2. 
   Eating in weightless conditions isn`t easy.
   

3. 
   Taking enough exercise is difficult.
   

4. 
   Being in good health is very important for astronauts.
   

5. 
   Imagining what astronauts have to do is difficult.
   

6. 
   Living a completely normal life in space is impossible.
   

7. 
   Going into space is never boring.
   

8. 
   Returning to Earth makes most astronauts feel happy. Most astronauts feel to Earth.