Hello
rebrik,
It's possible that someone will overrule me here, but in my way of thinking
all progressive forms are marked by virtue of their being progressive. Simple Present forms are unmarked, because the fundamental meaning of Simple Present is that the user wants to express what he sees as "fact"...period, with no
marking for any other nuance of interpretation. There is nothing there about time, or remoteness (which is the essence of Simple Past forms), or personal judgment (the point of modal auxiliaries), or anything else. Hence the form is said to be "unmarked". It is the
absence of marking which is the central characteristic of Simple Present.
But any and all progressive forms are
marked to show that the event described is extended-in-time rather than "simple" (or holistic). The -
ing suffix is put there for the purpose of suggesting that the event under consideration has a time of beginning and another later time of ending, so that it must be envisioned as a temporary, but time-consuming, event, however long or short it may be. This is quite separate from Simple Present views of an event, so the form must be seen as a
marked form. Remember too, that English grammar is a combinatorial system, so that all verb forms which have a progressive element add this
extended in time component to the overall meaning of the complete verb phrase.
You probably already know all of this, but it may help to have it expressed by someone else as a reinforcement. (Unless, of course, a better informed person can show both of us where we are wrong).
Larry Latham
Who, by the way, will be asking you this question? Is it for oral exams?