Answer:
1. Jeff promptly prepared to go snorkeling for the first time.
2. He carefully strapped on his face mask.
3. "You are learning fast," the instructor said.
4. Jeff plodded clumsily across the beach in his fins.
5. He quickly looked through his mask into an underwater world.
6. Brightly colored fish swam tirelessly in front of his eyes.
7. Jeff patiently snorkeled for several hours.
There are several options you could use. The ones I chose are not the only right answers. Hope this helps!