It was a pleasant and sunny aAugust day in a village ion the coast of New Bruswick, Canada. It was a pleasant and sunny August day in a village on the coast of New Bruswick, Canada.

It was a pleasant and sunny aAugust day in a village ion the coast of New Bruswick, Canada. It was a pleasant and sunny August day in a village on the coast of New Bruswick, Canada.

Never did they think that it could be dangerous walking near there, but in instantin the forest, but within seconds they got involved in the most terrorizing three hours of their lifves. Never did they think that it could be dangerous walking in the forest, but within seconds they got involved in the most terrorizing three hours of their lives.

You could also say "They never thought that it could be dangerous~" but I have seen writers use the passive form like this for stylistic purposes.

Never did they think that it could be dangerous walking near therethrough the woods, but in an instants they got involved in the most terrorizing three hours of their lifves. Never did they think that it could be dangerous walking through the woods, but in an instant they got involved in the most terrorizing three hours of their lives.

Things seems to be calm until, out of nowhere, without warning, a serious accident happens or you get a major illness that changes everything. Things seem to be calm until, out of nowhere, without warning, a serious accident happens or you get a major illness that changes everything.

Personally, I would take out "you get a major illness" part. In written language, using the subject pronoun "you" in the middle of a sentence sounds very informal and interrupts the flow of the sentence. If it were me I would write "~~a serious accident or major diagnosis change everything."

Things seems to be calm until, out of nowhere, and without warning, a serious accident happens or you get a major illness that changes everything. Things seem to be calm until, out of nowhere and without warning, a serious accident happens or you get a major illness that changes everything.

When they looked back, less than ten meters behind them, there was a giant black bear! When they looked back, less than ten meters behind them, there was a giant black bear!

When they looked back, there, less than ten meters behind them there, was a giant black bear! When they looked back, there, less than ten meters behind them, was a giant black bear!

That caused an immenseis scare ind the boys immensely, but they had not much fear, because tlittle to fear. They had read that black bears tend to keep away from people. This scared the boys immensely, but they had little to fear. They had read that black bears tend to keep away from people.

The passive voice sounds unnatural here and should probably be avoided unless you are using it for very specific stylistic reasons. I broke up the sentences to make it easier to digest the information.

That causedIt gave the boys an immense scare in the boys, but they had not much fear, but they quickly became less afraid, because they had read that black bears tend to keep away from people. It gave the boys an immense scare, but they quickly became less afraid, because they had read that black bears tend to keep away from people.

The first to lines of your writing were kind of contradictory, but I guessed as best I could.

Then, they started to getback away really slowly. Then, they started to back away really slowly.

Then, they started to gret awayreat really slowly. Then they started to retreat really slowly.