Help understanding present continuous

Question

I have some question about present continuous. My text book was written like this. The present continuous is used that sometimes the action is not happening at the time of speaking. For example, Steve is talking to a friend on the phone. He says. I'm reading a really good book at the moment. It's about a man who...

Steve is not reading a book at the time of speaking.

at here, I don't understand the usage. How can I understand as to this usages? What does this implies ? Just it emphasis? Or just boast of himself?

Actually I can't understand when do I use this usages?

for another example, Kate wants to work Italy, so she is learning Italian.(but perhaps she isn't learning Italian at the time of speaking) Ok. Then what does it want to expression? Why this sentence used by -ing ?

Answer 1

The present progressive/continuous does not necessarily mean that an action is taking place at the moment of speaking. "It expresses the speaker's view of the event as having limited duration" (Michael Lewis, The English Verb, 1986.97).

1.Steve is in the study. He's reading a book.

In [1], Steve's reading of the letter has duration; it started before the moment of speaking/writing and continues after it. That duration is limited; some (unspecified) time ago we know that he was not reading, and at some (also unspecified) time in the future, when he reaches the end of the letter, he will stop. The Progressive (Continuous) Aspect, sometimes, denotes a situation in progress at the moment of speaking.

2. Kate wants to work in Italy. She is learning Italian.

In [2], the limited duration of the activity is evident from the context. Unless uttered by the speaker when Kate is in the middle of her Italian studies, then the action is not necessarily taking place at the moment of speaking.