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问题 选择题

No sooner______ themselves in their seats in the hall than the speaker began his speech.

A．they settled

B．had they settled

C．did they settle

D．they had settled

答案

答案：B

题目分析：句意：他们一在座位上坐下，演讲者就开始他的演讲。no sooner…than…,hardly…when…结构中，主句应用过去完成时的倒装结构。故选B。

单项选择题 案例分析题

患者男，60岁，既往有慢性乙型肝炎病史30年，近半年自觉消瘦、乏力，体重减轻约10kg。查体：一般情况好，皮肤巩膜无黄染，腹平坦，腹腔积液征（-）。肝功能ALT63U/L，AST52U/L，TBil40.0μml/L，ALB32g/L。

根据第6版AJCC肝癌分期，该患者属于（）

A.临床Ⅰ期

B.临床Ⅱ期

C.临床Ⅲa期

D.临床Ⅲb期

E.临床Ⅳ期
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问答题

Eukaryotic repressors抑制因子work invarious ways, just as they do in bacteria However, the simplest and most common mechamsm seen in bacteria is for the repressor to bind to a site overlapping the promoter, thus blocking binding RNA polymerase. That mechanism is not typically seen in eukaryotes. Most commonly, cukaryotic repressors work by recruiting(招募)histone modifiers that reduce transcription. For example, where as a histone acetylase(乙酰比酶)is typicallyassociated with activation, a histone deacetylase (去乙酰化梅)——that is，anenzyme that removes acetyl groups——acts to repress a gene. In some cases, long stretches of nucleosomal DNA can be kept in a relatively insert(无活性)state by appropriate nucleosome modification, most notably decetylation and methylation.
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