求翻译：英文摘要所用的时态一般有两类一是全用一般现在;二是不同场合用不同时态。后者主要是用一般现在时和一般过去时。一般现在时用于描述研究目的和范围、研究内容、结果和结论;一般过去时用于描述论文撰写前作者已做的工作,也可用于表示转述已发表文献的报导、讨论和研究内容。是什么意思？

null

The English summary there are generally two tenses Class A is the use of general now; second is the different occasions, not at the same time. The latter is used mainly when the General now and general of the past. When used to describe general now purpose and scope of the study, research, results a

English abstract uses the tense has two kinds one is generally all uses the general present; Two is the different situation uses the different tense.The latter mainly is with the general present when and past indefinite tense.When general present uses in describing the research goal and the scope, t

English summary of the tenses generally have two types one is full in the present two different occasions with different tenses. Primarily in the simple present and simple past tense. The present tense is used to describe research purpose and scope, content, results and conclusions of past tense is

null