Answer:
The narrator believes that fog is something fast, but very involving and comprehensive.
Step-by-step explanation:
The lines presented in the question above belong to the poem "The Love Song of J. Alfred Prufrock" written by T.S. Eliot. The poem portrays the loss of authority and how this influences a sense of isolation, devaluation and alienation in human beings.
In the lines shown above, we can see how the speaker reflects on the passage of a fog, which, although very fast, has the ability to interact with various elements of the city, in a furtive, but intense and comprehensive way.