揩别人油，占别人便宜可以说 to sponge off someone 就好象是个sponge 擦呀擦的。
He's 30 years old, but still lives at home and sponges off his parents.
他都30岁了，还是住在家里啃老。
John is a miser. He always sponges off his friends.
他是个小气鬼，就知道占朋友便宜。
sponge a meal off him 蹭他一顿饭
sponger爱蹭吃蹭喝占便宜的人
take advantage of others 占别人便宜
stingy 小气的
cheap也能表示小气的
cheap-ass/miser 小气鬼
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