Based on this excerpt from Ernest Hemingway's "In Another Country," what is the contextual meaning of the phrase "take up"? "Ah, yes," the major said. "Why, then, do you not take up the use of grammar?" So we took up the use of grammar, and soon Italian was such a difficult language that I was afraid to talk to him until I had the grammar straight in my mind.
talk to him until I had the grammar straight in my mind.

to become interested in or engaged in something
to begin to hold or work at a position or post
to occupy time, space, or the attention of someone
to pursue a matter later or further with someone