Используйте модальные глаголы должны в правильной форме, чтобы соответствовать каждому пробелу.
The birds. leave the town if we don’t build up nesting boxes. (HAVE TO)

Ken
clean out the pond. (NOT HAVE TO)

We
collect the rubbish during the rain yesterday. (HAVE TO)​

Hazel: Yes. I am finishing a piece of homework for tomorrow. Why? What are you doing?
Jeremy: Well, I am thinking about my homework, but I'm afraid I am not actually doing it at the moment. I'm tired and bored. Do you want to go out?
Hazel: No. Look at the weather. It is raining. I never go out in the rain. By the way, do you know the new girl in our class, the one with glasses? I think she comes from Venezuela. Anyway, she is staying with Peter's family this month.
Jeremy: Yes, I know. she is doing well at school, isn't she? Peter says she speaks three languages: Spanish, English and French. I don't speak any languages!
Hazel: Tired, bored and stupid! Why would I want to go out with you, anyway?

Colonisation of the Moon or other planets in the Solar system might be necessary one day.  People over-use natural resources and sooner or later there will be no gas, oil or coal,  Air and water will be so polluted that people will have to look for homes on other planets.  It wouldn't be desirable but quite possible.  The problem is that the humanity has no technology to travel to other planets and to remain there for ever.  Governments prefer to spend money on weapons instead of inventing technologies to save our planet.  I personally believe that moving to other planets might be a disaster for the people.  They wouldn't be able to survive there.  Sadly enough, there are no suitable planets in the Solar system where we could settle. I wouldn't like to live in the metal box on some dead planet all my life.  Though if we go on the way we do now, Earth will also become a dead planet.