一般的Original Article 通常包括 Abstract, Introduction, Materials and Methods, Results, Discussion, Conclusion 這幾個部分，每個部分大概有什么內容大家應該都有了解吧？其它類型的文章也都可以根據這種類型舉一反三，那我就直接以Original Article為例講時態運用了哈。

摘要（Abstract）：

一般情況下，研究背景，實驗目的，論文結論，采用一般現在時。實驗方法，結果及發現，采用過去時。舉幾個栗子：

研究背景：A method to select non-responders as early as possible is essential for preventing unnecessary toxicity.

實驗方法：Human breast cancer cells were injected into nude rats.

實驗結果：A new in vivo breast cancer model was successfully established.

論文結論：The present study suggests that ...

當然，有些雜志也會專門有些比較“特別”的要求，比如Cell，要求Abstract全部使用一般現在時。大家可以自行體會下：

Here we present a unifying hypothesis about how messenger RNAs, transcribed pseudogenes, and long non-coding RNAs “talk” to each other using microRNA response elements (MREs) as letters of a new language. We propose that this “competing endogenous RNA” (ceRNA) activity forms a large-scale regulatory network across the transcriptome, greatly expanding the functional genetic information in the human genome and playing important roles in pathological conditions, such as cancer.

前言（Introduction）：

這部分用到的時態很多變，不能一概而論。

研究背景描述的如果是經典原理，事實，或目前為止最前沿的結果，作者寫論文時仍認為是正確的（即使是曾經發生的），用一般現在時。

比如：CircRNAs are recently identified as a naturally occurring family of noncoding RNAs that is highly represented in the eukaryotic transcriptome.

描述已經完成的事，強調 “曾經”，目前為止對此持肯定態度，用現在完成時。

比如：A large number of circRNAs have been successfully identified in various cell lines and across different species.

曾經的研究，其結果現在為止仍然正確，則一句話中可以既有完成時，也有一般現在時。

比如：Recent studies have shown that exon circularization is facilitated by complementary sequences and regulated by specific protein factors.

以作者為主語，闡述曾經的研究結果，如果該研究結果仍然正確，則謂語動詞用過去時，從句中仍使用一般現在時。

比如：Poliseno et al. recently proposed that the high sequence homology enables pseudogenes to compete with their parental genes for a shared pool of common miRNAs.

曾經的研究，但已經過時或失效，作者懷疑其正確性，或要否定其正確性時，用過去時或過去完成時。

比如：Nevertheless, these species had generally been considered to be of low abundance and likely representing errors in splicing.

LincRNA-p21 was initially identified as a direct transcriptional target of p53.

材料與方法（Materials and methods）：

描述寫論文之前作者所做的工作，用一般過去時。

比如：The proliferation of Huh-7, HCT-116, HeLa cells was tested by CCK-8 kit.

這部分一般時態變化比較少，沒什么爭議。

結果（Results）:

描述自己的研究結果，因其發生于寫作之前，用過去時。

比如：In total, 67,358 distinct circRNA candidates were found in these tissues and 27,296 of these circRNAs contained at least two unique back-spliced reads.

但是，單純描述結果呈現形式（圖或表），或直接用圖或表作為主語時，因為是寫作當時發生的事，所以使用一般現在時。

比如：A detailed summary for each sample is provided in Supplementary Table 1.

Figure 1 shows the mean spectra for the original data.

討論：

對此次研究結果的總結，用過去時。

比如：In this study, we identified lincRNA-p21 as a key regulator

of cell proliferation and apoptosis.

對Results部分的結果描述進行更深入的分析和討論,闡述結果的意義，用一般現在時。

比如：However, certain circRNAs are predominately expressed in one gene locus and present at substantial levels that suggest these species are purposefully produced.

結論：

強調過去的研究成果采用過去時，表達將來的研究方向或研究前景用將來時。

比如，In conclusion, our study provided a portrayal of circRNAs in different human normal and cancerous tissues.

闡述自己研究成果的意義用一般現在時。

比如，Taken together, these lines of evidence reveal a new level of diversity in the transcriptome and their regulation in human cells.

提出研究前景或將來的研究方向用將來時，這部分也可能出現在Discussion中。

比如，It will be interesting to explore whether lincRNA-p21 can interact with epigenetic factors