I checked my sentences once more. I included the last sentences for you to correct. Thank you.

1) The natives loved him because he had the guns and they hadn't seen anything like them before.
2)He was looked up to by the natives because of his guns.
3)The first company trading post was a depressing place. African people were tied together with chains. There were black bodies lying on the ground all around Marlow waiting for their end to come.
4)He stood out in his ironed and starched white shirt. He looked as if he worked in a big city and not in that terrible place.
5) Marlow travelled on foot for the next two hundred miles. He reached the central station after 15 days.
The manager was so successful in his job because he never fell ill and could survive the heat and the poor diet.
6) He told him he was the chief of the inner station. He was a brilliant man, who represented compassion, science, and progress. He was sent to them from Europe. According to him, Mr. Kurtz would be a great man in two years’ time.
7) The agent wanted to become a station manager because he could make a lot of money dealing with ivory.
8) It took him a lot of time to obtain the rivets he needed to repair the steamer. The manager hoped that Kurtz would be dead by the time they got there.
9) It consisted of little groups of men that arrived at the station in search of ivory. There was always a white man in charge. He sat on a donkey and gave orders to the native carriers who accompanied them (him).

No errors.

Sra