中介语石化现象及其对外语教学的启示

中介语石化是二语习得中的一个普遍现象.本文介绍了中介语石化现象的分类,分析了它产生的原因,并提出了避免中介语石化现象、活化外语教学的策略.     

中介语石化现象及其对外语教学的启示

中介语石化是二语习得中的一个普遍现象。本文介绍了中介语石化现象的分类,分析了它产生的原因,并提出了避免中介语石化现象、活化外语教学的策略。     

中介语石化现象分析及对外语教学的启示

中介语石化是二语习得中一个普遍存在的现象。通过介绍、分析中介语石化的类别和成因,对中国学生出现中介语石化现象提出了几点教学建议。     

中介语石化现象及其对少数民族地区外语教学启示

中介语石化现象是二语习得中的一个普遍的、不可避免的现象,本文以Selinker的观点为主要理论依据,多角度分析了中介语石化现象的成因,对于少数民族地区外语教学中如何避免中介语石化现象提出一些建议。     

英语写作中中介语石化成因研究

中介语石化是二语习得中的普遍现象也是外语写作教学中的一个难题。本文对国内外近30年关于语言石化现象成因的研究进行了综述，并在中介语理论的基础上，从词汇、语法、文化迁移和训练迁移等方面阐述了中介语的石化对英语写作的影响，提出了防止和减少中介语石化、提高英语写作水平的相应对策。     

二语习得中介语及石化现象综述

中介语石化是二语习得中的一个普遍现象。本文对二语习得,中介语,以及石化现象之间的关系进行评述。文中探讨关于这方面历来的研究手段,观点的发展演变过程,以及中介语石化对我国外语教学的启示和意义。     

中介语石化现象产生的原因及其对策

在二语习得的研究中,中介语的研究占有很重要的地位。中介语指学习者在学习第二语言的过程中产生的介于母语和目的语之间的一种语言状态。通过学习,中介语不断趋向于目的语。然而在中介语的研究中,中介语石化的研究又是一个很重要的切入点。本文将对中介语石化现象产生的原因及防止产生石化现象的对策进行探讨,进而指导第二语言的教与学。     

浅析中介语石化现象与大学英语教学

中介语石化现象是二语习得中的一个普遍现象。近40年来,国内外很多研究者对中介语石化现象的成因从不同的角度进行了深入全面的分析。中介语的石化能从不同角度对大学英语教学产生丰富启示。教师要提高对此现象的关注度,促进大学英语的教与学。     

中介语与石化现象

中介语是第二语言学习过程中学习者把母语语言规则转移到第二语言的语言规则、运用母语语言规则简化第二语言的语言规则的产物.本文从中介语的概念出发,简单介绍了中介语的特征,说明了中介语石化产生的认知方面的原因,并对防止石化现象的防止提出了几点建议.     

试论中介语石化与中式英语

中介语是学习者在第二语言习得过程中的必经阶段，中介语的石化是二语习得中的普遍现象。中式英语是中国人学习英语的过程中最常见的问题，是一种中介语现象。文章在中介语理论的基础上从不同层面描述了中式英语的表现，并探讨了中式英语的成因，提出了避免中式英语产生和中介语石化的相应对策。     

末次间冰期赵店动物群的地层时代探讨

报道了在山西襄汾赵店采砂场,黄土下部砂层中发现了哺乳动物群化石,并对化石出土层位的时代和古环境进行了分析.在赵店的动物群化石中除最后鬣狗和虎外,基本上与丁村动物群相同,出土层位也与丁村组相似.从化石出土层位上覆黄土古土壤序列分析,化石层与S1古土壤发育时代相当,其时代上限为距今7.5万年,当属末次间冰期,气候相对温暖湿润.     

黄河中游黄土区古土壤分布特征及其反映的古气候意义

本文对黄河中游地区古土壤分布特征提出了一些新的认识。该区有过约50决温湿到干冷的古气候波动,形成了约50层古土壤,并将其划分为5个古土壤组合带。     

植物细胞质化石研究进展

 近年来古植物学研究表明,植物细胞质确实可以保存为化石。随着相关研究技术的进步,研究发现植物化石中具有和现代植物相似的超微结构。特殊情况下,植物细胞质化石研究能够帮助解决现代生物学中某些难以解决的问题。高温和野火在植物细胞质化石的形成过程中起到了重要作用,而一个过去被古生物学家视而不见的自然现象--雷电可能对某些超微结构的固定起到了关键作用。植物细胞质化石研究把古植物学推向一个新的研究层面和方向,促进了与其他学科之间的融合,也把一些新的研究手段引入到了古生物学中。本文回顾植物细胞质化石的研究历程,总结研究成果和经验,并对未来发展趋势进行了展望。     

Preliminary notes on softbodied fossil concentrations from the Early Cambrian Chengjiang deposits

The Chengjiang fauna has played a pivotal role in our understanding of the origin and diversification of metazoans since its discovery in 1984. To date, this fauna has been documented as consisting of 121 genera with 140 species belonging to 24 phyla[1-27]. The geo- graphic distribution of the Chengjiang fauna has been expanded from Chengjiang County to eastern Yunnan Province including Haikou, Malong, Yiliang, Anning and elsewhere[25-33], with about 20 localities in to- tal[25,33]. Succes…     

A Chengjiang-type fossil assemblage from the Hongjingshao Formation （Cambrian Stage 3） at Chenggong,Kunming, Yunnan

A new Chengjiang-type fossil assemblage is reported herein from the lower part of the Hongjingshao Formation at Xiazhuang village of Chenggong,Kunming,Yunnan.The fossil assemblage,named as Xiazhuang fossil assemblage,yields predominantly soft-bodied fossils,including arthropods,brachiopods,priapulids,lobopods and some problematic taxa,with arthropods being the most dominant group.Preservation and composition of the fossil assemblage are very similar to the typical Chengjiang biota,which is preserved in the middle Yu’anshan Formation in the large area of eastern Yunnan.The associated trilobites demonstrate that the soft-bodied fossil assemblage belongs to the late Qiongzhusian in age(Stage 3,Cambrian),suggesting that the Hongjingshao Formation is probably a diachronous lithostratigraphic unit ranging from the upper Qiongzhusian to the lower Canglangpuan stages in eastern Yunnan.The fossil assemblage from the Xiazhuang area fills up the missing link between the typical older Chengjiang biota and the younger Malong and Guanshan biotas,making eastern Yunnan a unique area in the world to reveal the early evolutionary history of animals and palaeocommunity dynamics during the‘‘Cambrian explosion’’.     

Evolution and environment in the Hominoidea.

Between 10 and 20 million years ago, a variety of hominoid primates lived in Africa, Europe and Asia. The question of which of these, if any, lie closest to the ancestries of humans and modern apes remains a lively source of debate. Recent fossil discoveries, though, shed light on the environments in which the various groups of hominoid emerged and, it is hoped, on their evolution. But the lack of a hominid fossil record before about 5 million years ago--and any fossil record for the African apes--is still a frustrating barrier.     

海相化石群落识别的一种方法——以广西六寨泥盆系东岗岭组化石群落的识别为例

化石群落的识别是古代生物群落研究的基础．目前缺少普遍遵循的化石群落识别的原则，识别方法差异很大，这影响了古代群落研究的广度及深度．根据广西六寨泥盆系东岗岭组化石群落的研究实例，所提出的海相化石群落的一种识别方法，为解决识别方法上存在的分歧，提供了一条途径．该方法以注重群落与环境的整体性为原则，在沉积环境确定的基础上，依据化石群总体面貌（化石类型及其相对丰度）与沉积相带类型的对应性，来识别化石群落．     

Using the fossil record to estimate the age of the last common ancestor of extant primates

Divergence times estimated from molecular data often considerably predate the earliest known fossil representatives of the groups studied. For the order Primates, molecular data calibrated with various external fossil dates uniformly suggest a mid-Cretaceous divergence from other placental mammals, some 90 million years (Myr) ago, whereas the oldest known fossil primates are from the basal Eocene epoch (54-55 Myr ago). The common ancestor of primates should be earlier than the oldest known fossils, but adequate quantification is needed to interpret possible discrepancies between molecular and palaeontological estimates. Here we present a new statistical method, based on an estimate of species preservation derived from a model of the diversification pattern, that suggests a Cretaceous last common ancestor of primates, approximately 81.5 Myr ago, close to the initial divergence time inferred from molecular data. It also suggests that no more than 7% of all primate species that have ever existed are known from fossils. The approach unites all the available palaeontological methods of timing evolutionary events: the fossil record, extant species and clade diversification models.     

Absolute measures of the completeness of the fossil record

Measuring the completeness of the fossil record is essential to understanding evolution over long timescales, particularly when comparing evolutionary patterns among biological groups with different preservational properties. Completeness measures have been presented for various groups based on gaps in the stratigraphic ranges of fossil taxa and on hypothetical lineages implied by estimated evolutionary trees. Here we present and compare quantitative, widely applicable absolute measures of completeness at two taxonomic levels for a broader sample of higher taxa of marine animals than has previously been available. We provide an estimate of the probability of genus preservation per stratigraphic interval, and determine the proportion of living families with some fossil record. The two completeness measures use very different data and calculations. The probability of genus preservation depends almost entirely on the Palaeozoic and Mesozoic records, whereas the proportion of living families with a fossil record is influenced largely by Cenozoic data. These measurements are nonetheless highly correlated, with outliers quite explicable, and we find that completeness is rather high for many animal groups.     

New discovery of fossil cycad-like plants from the Middle Jurassic of West Liaoning,China

The Cycadales are one of the most ancient lineages of seed plants, with a fossil record that extends over 250 mil- lion years. Cycads are believed to have originated from the Late Palaeozoic, and reached its maximum diversity and distribution during the Mesozoic; however, their evo- lutionary history has remained relatively poorly under- stood[1―4]. This largely results from the lack of anatomi- cally well preserved fossil evidence and reproductive re- mains. In recent years, more researche…