主动语态是一种更简单直接的写作方式。因而，相对于被动语态，大部分科学期刊都鼓励投稿人更多的使用主动语态[1]。

主动语态-主语为行动的实施方。
被动语态-主语为行动的接收方。

在撰写科学论文时我们会使用各种各样的时态。下面是一些在不同时态下使用主动语态和被动语态的例子。 
现在时-通常在概论，讨论和结论中使用的时态。
Example 1:
Active: Vitamin A increases the risk of hair loss.
Passive: The risk of hair loss is increased by vitamin A.

Example 2:
Active: Volatile organic compounds (VOCs) emitted from industries and vehicle exhausts can induce a series of environmental problems, including photochemical smog, broken ozonosphere, and environmental pollution.
Passive: A series of environmental problems, including photochemical smog, broken ozonosphere, and environmental pollution, can be induced by volatile organic compounds (VOCs) emitted from industries and vehicle exhausts.

现在时-通常在目标中使用的时态
Example 1:
Active: In this study, we present our design of an electric hot water tank.
Passive: In this study, a design of an electric hot water tank is presented.

Example 2:
Active: This study develops an efficient methodology to examine a space–time continuous dataset for urban irrigation water use.
Passive: An efficient methodology to examine a space–time continuous dataset for urban irrigation water use is developed in this study.

现在完成时-通常在概论，讨论和总结中使用的时态。
Example 1:
Active: Previous studies have used comparative analysis of ORF2 sequences to elucidate phylogenetic relationships among different FCV isolates.
Passive: Comparative analysis of ORF2 sequences has been used in previous studies to elucidate phylogenetic relationships among different FCV isolates.

Example 2:
Active: Only a small number of empirical studies have focused on the patterns and mechanisms behind disease clusters at small spatial scales, especially in wild host–pathogen systems [2].
Passive: The patterns and mechanisms behind disease clusters at small spatial scales, especially in wild host–pathogen systems, have been focused on by only a small number of empirical studies [2].

过去时：通常用于材料与方法/结果。
Example 1:
Active: We determined the presence of larvae by dip netting.
Passive: The presence of larvae was determined by dip netting.

Example 2:
Active: We evaluated the number of haplotypes (h), haplotypes (Hd), and nucleotides (π) using the DnaSP 5.10 program [3].
Passive: The number of haplotypes (h), haplotypes (Hd), and nucleotides (π) was evaluated using the DnaSP 5.10 program [3].

Example 3:
Active: We found a strong correlation between above-ground and below-ground biomass accumulation in Platanus occidentalis.
Passive: A strong correlation was found between above-ground and below-ground biomass accumulation in Platanus occidentalis.

然而，您应该尽量使论文中的语言容易理解。所以如需必要时也可以适量使用被动语态。

什么时候该用被动语态：
1. 当强调结果（接收方）而不是行动方（执行者）。
The risk of hair loss [product] is increased by vitamin A [agent].

2. 在同一段落中保持统一的主体和重点。
Female pattern hair loss is common but estimates of its prevalence have varied widely. The risk of female pattern hair loss is increased by vitamin A.

3. 如果不希望指明主体。
The procedures were somehow misinterpreted.

4. 当主体不可知或者不重要的时候。
Every year, thousands of people are diagnosed with cancer.

更多参考文献：
[1] Sainani K., Elliott C. & Harwell D., 2015. Active vs. Passive Voice in Scientific Writing. ACS Webinars. Available at: https://www.acs.org/content/dam/acsorg/events/professional-development/Slides/2015-04-09-active-passive.pdf [Accessed 20 June, 2016].
[2] Plotnick J. How to Use Active Voice in the Sciences. University College Writing Centre, University of Toronto, Canada. Available at:http://www.writing.utoronto.ca/advice/specific-types-of-writing/active-voice-in-science [Accessed 20 June, 2016].
[3] The Writer’s Handbook, 2014. Use the active voice. The Writing Centre, University of Wisconsin. Available at:http://writing.wisc.edu/Handbook/CCS_activevoice.html [Accessed 20 June, 2016].