My complex sentence

Walt. understand what a complex sentence
What is a complex sentence?

Number one My little sister is so irritating because she keeps jumping on me and it is so annoying for me and I have to keep looking after her but I still like her when she does that to me. She is my sister to look after so I have to keep her safe.
Number two Dolphin jumping out of the water because he liked to be watched so the dolphin can be famous.
Number 3 Tim Peake is a famous British astronaut because he liked to see the moon and be the first one on there so he can be famous who was that on there on the moon.

Number 4 The house on the hill remained unsold because it was too old for people to live in. Who was in that house it looks like that house is going to fall.
Number 5
The lion was licking his paws because there was a thorn although the lion was asleep.

Number 6
The dinosaur was hungry because he never been fed until two days ago the dinosaur was very very hungry.
Number 7 The aliens' scary spaceship came down because it was looking for something as It was the alien best friend the aliens' best friend was scared of the spaceship because it was big and shiny when the best friend saw the alien it wasn't scared anymore.
Number 8 The girl dived into the water because she was practicing for a swimming competition although she was late.
Number 9 After He had broken the world record for a high jump he had started to go crazy
Number 10 Science is an interesting subject although it is dangerous.