Here are the answers to your questions based on the context of the Montgolfier brothers and their invention of the hot air balloon:
Joseph Montgolfier got the idea for a flying machine when ... a) he saw smoke in a fireplace.
Joseph hoped to be a(n) ... b) engineer.
They burned straw to ... a) help the balloon go up.
The first flight was watched by ... c) a lot of people.
The Montgolfier brothers asked the king's permission to ... a) send animals up in the balloon.
If you need more information or further clarifications, feel free to ask!