Here's a sentence from a book "The Articulate Mammal: An Introduction to Psycholinguistics"
In speech, three processes, at the very least, are taking (1) place simultaneously: first, sounds are actually being(2) uttered; second, phrases are being(3) activated in their phonetic form ready for use; third, the rest of the sentence is being(4) planned.
What I don't understand at all, is why the author uses the present continuous tense in these places that I've marked in bold... I'd say this sentence like this:
1) [...] take place [...] 2) [...] sounds are uttered [...] 3) [...] phrases are activated [...] 4) [...] the sentence is planned.
The reason for this, I suppose, is that we use the present simple tense when (we're?) talking about general rules... and the author seems to be describing (seems to describe) some general rules when she talks (when she's talking?) about what processes take place (again: taking place?) in speech.
Hope that somebody will explain it to me, thx in advance!