Arabic and various other Semitic languages have two kinds of energetic moods, which express something which is strongly believed or which the speaker wishes to emphasize. Their exact meanings are dependent upon the prefix that is attached to them. For example, is in the long energetic mood and has strong obligation meanings; it means "he certainly writes" and if it is preceded by , , it will have the meaning of "he must write". The short energetic expresses weak obligation, e.g., which means "he almost writes"; if it is preceded by a prefix like , , it means "he should write".