1. Future historians will be in a unique position when they come to record the history of our own times.
    未来的史学家，如果要记载我们时代的历史，其处境必将独具一格。

2. Future historians will be in a unique position when they come to record the history of our own times.
    未来的历史学家在写我们这一段历史的时候会别具一格。

3. For most of the earth´s history they have been the only form of life on our planet.
    在地球上发展的大部分进程中，细菌是地球上唯一的生命形式。

4. For the Communist Party had come on the scene and that changed the whole course of China´s history.
    因为共产党已经登上了历史舞台，并且改变了整个中国历史的进程。