雪がバスを覆っている。

snow

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

bus; bath; bass

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to cover; to hide; to conceal; to wrap; to disguise