问题：为什么用进行时表达通常情况？

VOA新闻节选：

前面讲到：现在由于新冠状病毒的蔓延，世界上一半以上的学生失学，

接着看下面：

While more than half of the students around the world are out of school, some can attend remotely where

they have adequate technology.

Our teachers are coming to the school on a daily basis.

我们的老师每天都来学校。

They come in one after one or two together and they're prodviding their lessons to the students.

他们一个接一个地，或者两个人聚在一起，给学生们上课。

困惑：

表达通常的情况为什么用了进行时?（指Our teachers are coming to the school on a daily basis.）怎么理解这里的进行时呢?

另外，为什么接下来又用了一般现在时（指They come in one after one or two together）和进行时（指and they're prodviding their lessons to the students.）

麻烦老师解释一下，谢谢！