Can you please check if the following sentences are grammatically correct?

Thank you.
1) He invited him to his room for a drink and he accepted the invitation. 2) He spoke highly of Kurtz because he thought Marlow knew everything about the company.
3) As a matter of fact, both the agent and the manager felt threatened by Kurtz and wished he had never arrived. 4) They were jealous of his success because he could send more ivory than the other agents and had become a sort of idol for the natives.
5) Then the agent warned him that only animals could have a charmed life there in Africa.
6) Marlow asked him about the rivets, which were essential for repairing the steamer but the agent replied that he knew nothing about then.
7) Actually, he only obeyed the manager’s orders. The manager didn't want the steamer to be repaired as soon as possible because he hoped that Kurtz would be dead by the time they got there.
8) A few days later the Eldorado Expedition disappeared into the jungle. Meanwhile the rivets had arrived and Marlow began work on the steamer.
9) Marlow was excited at the prospect of meeting Kurtz soon. Once the steamer was ready, Marlow began his two-month journey to the inner station.
10) He drifted through that huge silence, which was sometimes broken by the sound of drums in the interior.

AOK = All OK

Sra