Which is the best way to increase your background knowledge?

Which two pronouns in the paragraph have unclear antecedents? cleaning the closet yesterday i cleaned my closet and dusted it thoroughly. i found receipts in a few of my jeans. i folded them neatly and put them in my drawer. i found an old box decorated with ribbons and a pink bow. it still looked pretty and new. in the bottom drawer, there was a bottle of perfume that mom bought in sweden. the perfume is old, but it still has a fresh, flowery scent. next to the perfume there was an old postcard that dad sent when he visited china.