1. Understanding how transcription is regulated is complicated by the many states of gene expression, ranging from completely silent to highly induced
主语：Understanding how transcription is regulated
谓语：is complicated by
表语：the many states of gene expression,
伴随状语（解释说明）：ranging from completely silent to highly induced。
伴随状语用来修饰动词，表示与谓语动词同时进行，即伴随着谓语动词的动作同时进行。如：
- He said it angrily, pointing at the notice on the wall. 他生气地说着，手指着墙上的布告。
这里，point与said同时进行，因此，pointing在这里是现在分词作伴随状语。
分词、with复合结构、独立主格、介词短语等都可以作伴随状语，比如
（以下例子中，括号里的部分都是伴随状语）
1.使用分词形式
The dog entered the room, (following his master).
这条狗跟着主人进了屋。
2.用with复合结构
The little girls were playing with snow (with their hands frozen red).
小女孩们在玩雪，手都冻红了。
3.用独立主格结构
The little boy goes to school, (the little dog accompanying him every day).
这小孩每天去上学，那条小狗陪伴着他。
4.用形容词
Crusoe went home, (full of fear).
克鲁索满怀恐惧地回家。
5.用名词
He went away (a beggar) but returned (a millionaire).
他讨吃要饭离家，腰缠万贯回归
2. Truly silent genes include cell- and lineage-specific genes whose expression is never needed in a different cellular context.
主语： Truly silent genes
谓语： include
宾语： cell- and lineage-specific genes
定语从句：whose expression is never needed in a different cellular context.
3. Other genes are repressed under certain conditions but are activated upon changes in the physiological or developmental state of the cell.
主语： Other genes
谓语：are repressed
but 引导的并列句。
4. Non-expressed genes may still be associated with paused RNA polymerases, poising these genes for rapid activation.
主语：Non-expressed genes
谓语：may still be associated with
宾语：paused RNA polymerases
伴随状语（解释说明）：poising these genes for rapid activation.
5. Other genes are expressed at a basal level under normal conditions prior to high-level activation upon stimulation.
主语：Other genes
谓语： are expressed at
宾语：a basal level under normal conditions
状语：prior to high-level activation upon stimulation.
6. Activation itself often occurs in bursts, rather than sustained high-level polymerase activity.
主语： Activation itself
谓语：occurs
宾语： in bursts
状语从句：rather than （occurs in）sustained high-level polymerase activity.
7. Each of the above gene expression states is associated with particular chromatin states, including different levels and compositions of histone acetylation.
主语：Each of the above gene expression states
谓语：is associated with
宾语: particular chromatin states
伴随状语：including different levels and compositions of histone acetylation.
8. The many acetylation sites within each histone provide a wealth of regulatory potential and have been reviewed extensively (Choi and Howe, 2009; Latham and Dent, 2007)
主语：The many acetylation sites within each histone
谓语：provide
宾语：a wealth of regulatory potential
and 的并列句。
9. Here, we focus on the functions of a few specific acetylation events involved in particular structural features that control gene expression.
主语：we
谓语：focus on
宾语：the functions of a few specific acetylation events
定语从句1：involved in particular structural features
定语从句2：that control gene expression
10. Chromatin structures at gene promoters are typified by a nucleosome-free region (NFR) flanked by well-positioned nucleosomes, referred to as –1 and +1 nucleosomes, reflecting their positions relative to the transcription start site (TSS).
主语：Chromatin structures at gene promoters
谓语：are typified by
宾语1：a nucleosome-free region (NFR)
宾语2：referred to as –1 and +1 nucleosomes
定语： flanked by well-positioned nucleosomes
伴随状语：reflecting their positions relative to the transcription start site (TSS).
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