To infer the meaning of a passage, a reader must select all that apply.
do a close reading of the text
guess until the right answer is found
check an encyclopedia to find the answer
use details as clues to the meaning

I believe the answers are: A "Do a close reading of the text" and D "Use details as clues to the meaning".

when i skim a text i look for anything i'm trying to find, like keys or clues or i just want to see if it is interesting to me.

explanation:

they are most likely about to fight in the battle of gaul