35.

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

The former sentence "He and many other athletes occasionally slow down to run side by side and chat with each other" The second sentence "There are also other athletes who are more focused on competition" here uses of course to express the emphasis on the latter sentence, which is in line with the inter-sentence relation.

Item A: The latter sentence of to illustrate needs to explain the previous sentence, which is wrong.

Item C/D: Indicates that "in addition" is a supplement to the content of the previous sentence, and the content of the previous and subsequent sentences here is different, so it is wrong.