Prosecutorial immunity

确实没有时间写自己想的东西，而且，为了能够尽快习惯英语思维，我尽可能试图避免太多地使用中文写东西（甚至是思考）。但是，为了能够留下一些自己日常活动的线索，我将拷贝一些从维基百科上查到的专业术语到这里，以此作为誌念。

In United States law, Prosecutorial immunity (or immunity from prosecution) occurs when a prosecutor grants immunity, usually to a witness in exchange for testimony or production of other evidence. It is immunity because the prosecutor essentially agrees to never prosecute the crime that the witness might have committed in exchange for said evidence.
This form of immunity generally comes in two forms. Blanket immunity (sometimes known as "transactional immunity") completely protects the witness from future prosecution for crimes related to his or her testimony. Use immunity only prevents the prosecution from using the witness' own testimony against them. However, should the prosecutor acquire evidence substantiating the supposed crime -- independent of the witness's testimony -- the witness may then be prosecuted for same.
While prosecutors at the state level may offer a witness either use or blanket immunity, at the Federal level use immunity is the norm.

Copied from Wikipedia http://en.wikipedia.org/wiki/Prosecutorial_immunity