原文肯定，翻译后为“不+否定”，有意想不到的效果，如：语气缓和或汉语中没有此种表达方法

1. Wet paint. 油漆未干

2. Keep upright. (Handle with care.) 切勿倒置（小心轻放）

3. Admission by invitation only. 非请莫入

4. If it rains in Cleveland today, volunteers will stand in lines with umbrellas to keep voters dry.

如果今天克里弗兰下雨，志愿者将打着伞排着队，以免选民淋湿。

5. If any mater should be added after this contract comes into force, then such a matter shall be agreed upon by both sides through friendly consultations and confirmed by means of exchanging official documents.

本合同生效后如有未尽事宜，须经双方友好协商同意，并交换正式文本以确认

注意：表达法的正反转换要根据具体情况，主要出于两点：

1、 表达习惯；

2、语气的缓和与加强