Chinese prepositions are similar to English prepositions to introduce an non-argument.
w˘o y`ong bˇa xi˘ao d¯ao d˘ak¯ai -le x`ın-f¯eng
I opened the envelope with a small knife.
However, unlike English prepositions, Chinese prepositions may function as full-fledged verbs. Therefore, they are also treated as co-verbs.
tā dí wén zhāng yòng liǎo hěn duō diǎn gù
His article made use of many literary quotations.
Reference: Chinese: a linguistic introduction by Chao Fen Sun