网友这个问题，需要从语用学方面分析。

从语用角度看，使用一般现在时表示正在进行的动作，完全是为了“简练”！

感叹句、倒装句、演示解说、体育比赛解说等，使用一般现在时情况居多。一般现在时的特点是：动词不用变化，最多单三加“s”，省去了am/is/are 和 -ing 的麻烦。网友的几个倒装句，也是为了简练，用最少的字数，尽快“提醒对方”，避免啰嗦。所以，完全倒装句没有进行体，多为一般体。“解说” 时需要速度，需要同步，用一般现在时，干脆又简练！

星火语法全解 说一般现在时可以表示正在发生的动作 

这个说法不能说错，但却是有误导性的，或者说是得看读者什么水平的。

至少它就在哪些场合可以用一般现在时来表正在发生的事, 那个场合、条件要讲清楚。

所谓一般现在时表示“正在发生的动作”，主要是两方面：

1. 一些固定表达（历史沿袭的原因）； 2. 历史现在时。

可以看看下面的话：

CGEL：P181

[a] In older English, the simple present was used more widely with reference to a present event which would now be described by use of the present progressive: Shakespeare's I go, I go may be contrasted with the present-day I'm going. Some relics of this archaic usage are found in one or two fixed expressions such as How do you do? and How goes it?

从这里，多少可以找到一些Here comes the bus的影子。

但据我所知，这样的表达应该是受了法语的影响，属于pat question问题。

类似的句子还有，I come to apologize. 

各种语言有自己的逻辑，比如这些句子用汉语套，都是很正常的句子，但英语里，只能是属于特殊现象了。Here comes the bus.这样的句子，说是固定用法，反而是知其然的解释。简单地说，我们不能用臆想的方式来解释它，没意思，接受就行了。

看看老外怎么说：

I'm afraid I can't give you an explanation as to why we use "Here he comes," but we also use "There he goes" in the same situation. Perhaps it's just an idiom...

不说英语是这位的母语，至少人家上的大学世界排名恐怕也不会差。

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How hard it snows!

这是感叹句，感叹句是描述而不是叙述，所以它的动词无论是动态动词还是静态动词，

在我们面前，都是静态性质的。因为我们并不是在说它动作的进程，而是犹如在看一个画面那样。

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延伸阅读：

[b] On the closely related dramatic use of the present,  cf 4.8,4.10.

[a] The simple present is usually used in newspaper headlines to report recent events: Trade unions back merger; 'No sell-our' says P.M. ; Economic think-tank seeks assurances. (On headlines, cf further 11.46).

[b] Two further minor uses of the historic present are (i) in photographic captions, for which, however, the -ing participle is an alternative form:

The Queen arrives / arriving for the State Opening of Parliament. and

(ii) in historical summaries or tables of dates:

1876 - Brahms completes his first symphony.

[c] There is variation between past and present tenses in cross-references from one part of a book to the other: This problem is / was discussed in Chapter l . The choice depends on whether the book is conceived of as existing at one time, like a static object; or whether it is imagined to progress in time, as it does for the reader who begins at Chapter 1 and moves from 'earlier' to 'later' parts of the hook. Other verb constructions (eg the perfective construction or the modal construction with will) may also be used to imply progression in time: This matter has been touched on in Chapter2, but we will return to it in Chapter