I do not know whether you realize it, but this condition is essential to us.
我不知道你是否了解,但是,这个条件对我们是必要的。
recorded for the slumbering scientist the strength of a shock that was too weak to waken him,and the direction from which it came.
由于地震太弱而未惊醒科学家时,就为科学家记录下了地震的强度和地震方向。