Выпишите из текста три предложения, в которых глагол-сказуемое стоит в Present Perfect. While I’m on the topic of who should or shouldn’t negotiate, I’d like to warn you about non-police negotiators.
The SOARU (Special Operation and Research Unit) points out that using “civilian” negotiators like members of the subject’s family, friends, clergy, a mental health professional, or an attorney is a high-risk proposition.

Since these people have generally not been trained in negotiation, they will probably, under the stress of the situation, revert to their usual way of talking with the subject. All negotiators have heard stories about family members who come to the scene and say, “Let me talk to him, he’ll listen to me”. When they get on the phone, some will call the subject a jerk; another will say, “Hang in there, Joey, we’re all proud of you”.
Clergymen, on the other hand, may get excessively moralistic or theological, while attorneys may have difficulty deciding which side they represent. Even mental health professionals with experience in crisis intervention may have little to offer if they have not had negotiation training. They are accustomed to people coming to them and asking for help, not resisting it. And, generally, they don’t have the mental “set” to expect demands and to deal with lying or threats if those demands aren’t ment. After getting negotiation training, however, they can work well as consultants to the negotiation team.
Finally, if a non-police negotiator is being used and you decide to go tactical, that person may be reluctant (or may refuse) to participate in a tactical response and may alert the subject by changing or disrupting the negotiations. So, unless there are specific reasons to the contrary, negotiators should be drawn from our trained officers, with professional consultants to back them up if necessary.