dander

例句：

1. 1. The dog was scratched by a flea, and now it's a real problem for the owner.
   这只狗被跳蚤咬了，现在对主人来说是个真正的问题。
2. 2.I bought an old book at the flea market, and it turned out to be really interesting.
   我在跳蚤市场买了一本旧书，结果发现非常有趣。
3. 3.The fleas on the dog are causing him a lot of discomfort, so we need to get rid of them.
   狗身上的跳蚤让他感到非常不舒服，所以我们需要把它们除掉。