Read about astronauts! Practice "have to", 4th grade English class

Hello students! Today we do a reading activity from your book. It's about astronauts.
I want you to pay attention to the expression "have to", which we are studying in this unit. It expresses obligation. For example:
Astronauts have to study a lot. They have to be fit and healthy. They have to wear a space suit.
Maybe one day one of you will be an astronaut too.