Конечно! Вот продолжение текста с использованием Past Continuous и Past Simple, подходящее для уровня A1:
Паст Континиус:
while Harry was swimming to the boat, he heard a loud noise.
and he was trying to listen carefully.
Паст Симпл:
Then he saw a big shark near him.
After that, he remembered something important.
Паст Континиус:
As he was climbing back onto the boat, he felt very tired.
While he was hiding behind the boat, he saw a gunshot.
Паст Симпл:
Harry called for help.
He found a case of money on the boat.
Suddenly, he felt ill.
Паст Континиус:
At the same time, he was talking to himself.
And he was trying to stay calm.
Паст Симпл:
Nearby, Harry heard a helicopter.
He saw people and wanted to tell them about the danger.
Если нужно, я могу дополнить или изменить текст.