现在进行时是英语中一个重要的时态，用来表示正在进行的动作。它的英文名称是Present Progressive Tense。当我们想要描述此刻正在发生的事情时，就会使用现在进行时。比如一个人正在跑步，这个动作正在进行中。
现在进行时的基本结构非常简单，由三个部分组成：主语加be动词加动词的ing形式。be动词会根据主语的不同而变化：I用am，he、she、it用is，you、we、they用are。例如'I am reading'这个句子，I是主语，am是be动词，reading是动词的ing形式。
The Present Progressive tense describes actions that are happening right now, at this very moment. It shows activities that are in progress or temporary actions occurring around the current time.
To form the Present Progressive, we use the formula: Subject plus am, is, or are, plus a verb with -ing ending. For example: I am working, She is reading, They are playing.
There are four main rules for adding -ing to verbs. First, most verbs simply add -ing directly, like work becomes working. Second, verbs ending in silent -e drop the e before adding -ing, like make becomes making. Third, short verbs with consonant-vowel-consonant pattern double the last letter, like run becomes running. Fourth, verbs ending in -ie change ie to y before adding -ing, like lie becomes lying.
现在进行时有三种基本句型。肯定句的结构是主语加be动词加动词ing形式，比如She is dancing。否定句在be动词后面加not，变成She is not dancing。疑问句把be动词提到句首，变成Is she dancing问号。这三种变化都是基于同一个基本结构。
现在进行时有三个主要的使用场景。第一，表示此刻正在进行的动作，比如I am studying now，我现在正在学习。第二，表示现阶段正在进行的动作，比如He is learning Chinese these days，他这些天正在学中文。第三，表示按计划即将发生的动作，比如We are meeting tomorrow，我们明天要见面。这三种用法帮助我们准确表达不同时间概念的动作。