【正文】
general nor the thesis explains and ments. Abstract should has strict structure, expression concise, exact semantic. We should think about what to write firstly, and what to write secondly according to the logic order. We should emphasize on the coherence between sentences each other. Abstract should be without the long sentence, and sentence should be simple. English abstract should use the tense and concise , monly general present tense, past tense, present perfect, using past perfect tense, we usually don’t use tense and other pound tenses . The voice, not only to consider