The present perfect continuous

Two sentences from the play in the simple past: "They lived in London before" and "I met her in a shop and asked her to come." The simple past puts an action in the past and leaves it there.

Now this one: "She has been staying with them for a while." That's a different tense: the present perfect continuous.

Its pattern: has / have + been + verb-ing: has been staying, have been preparing, has been growing.

We use it for two things, both about time stretching from the past to now:

1. How long something has been going on, started in the past and still continuing. "Mrs Shaw has been preparing the room since the morning." She started in the morning and is still at it! Words like for a while and since the morning fit this tense well.

2. Something going on recently, whose results show now. The focus is on the activity. "Mrs Shaw has been cleaning the room since morning" (and it's spotless now). "The students have been practising a play" (and they're ready).

Compare the two perfect tenses:

The been + -ing adds the sense of still continuing.

Practise: "The students have been preparing for weeks. The performers have been rehearsing every day, and their excitement has been growing."