Answer:
The eagle was circling his prey.
The eagle prepared to strike.
This is the example given, and we can join the two sentences using the word While.
The eagle was circling his prey while it prepared to strike.
So, to write a new sentence in a different way, we can do it in different ways:
While the eagle was circling its prey, it prepared to strike.
We can also make two distinct sentences and join them by using some conjunctions.
Example:
The boy cut the cake.
His boy was happy.
These two sentences can be made into one.
The boy was happy as he cut the cake.