parasite|parasites

他从不工作，只是个靠父母养活的寄生虫。

He never works and is just a ___parasite living off his parents.

这些微小的寄生虫会附着在鱼类的皮肤上吸取养分。

These tiny ___parasites attach to fish skin and feed on their nutrients.

那个年轻人整天游手好闲，完全是个靠父母养活的寄生虫。

That young man idles around all day, being a complete ___parasite living off his parents.