specialize ['spɛʃəlaɪz]：vi. 专门从事；详细说明；特化 vt. 使专门化；使适应特殊情况；详细说明 

例句：And bloggers who specialize in sharing news about trafficking have been threatened in the past.

句意：专门从事共享非法交易新闻的博客在过去受到过威胁。