Grammar Blog - Lesson 1
A man is waiting at the bus stop. Perhaps he started waiting five minutes ago, perhaps twenty minutes ago. You want to know. What do you ask?
"Are you waiting for the bus?" or "He's watching TV" are correct sentences. We call this tense the Present Continuous. In these examples it describes what is happening now; but when we talk about what has been happening up to now, and perhaps ask or say how long it has been happening up to now, we use the Present Perfect Continuous:
He's been watching TV since 6 pm.
He's been watching TV all evening.
He's been watching TV for three hours.
In these cases, the action began in the past, continues up to now, and may or may not continue in the future:
Note that we use for (with all tenses) to introduce the amount of time (for a moment/ for three hours/ for days/ for six months/ for many years/ for ages). We use since with the perfect tenses to introduce the starting point (since breakfast/ since half past two/ since Monday/ since Christmas/ since 2012). It can therefore be followed by a clause - a group of words with a verb: Since she left school/ since they arrived/since he took up golf.
Now doesn't always mean at this exact moment. "She's looking for a job" doesn't necessarily mean that she's going from one possible future employer to another at this moment, but that she has begun looking and not found one yet.
In the same way, I can say "I'm working in London at the moment", even if I'm relaxing in a park and visibly not working. This means that I normally work somewhere else - Birmingham, for example - but that my job at the moment is in London, for a temporary period. Perhaps I began working in London a week ago and will work here for another five weeks.
DANGER: The confusion arises if non-native speakers say: "I'm staying here for three days", when they really want to say "I arrived here three days ago", and "I'm staying here for six months".Native speakers will misunderstand them, and believe that they going to leave very soon!
Sometimes we use this tense to talk about our activity more or less up to now, without specifying how long, to say what we have been doing this evening, this week, etc.:
"I've been looking at the wedding photos"
"This week we've been working on the English tenses"
Some verbs have no normal continuous form. The next Grammar blog Verbs With No Usual Continuous Form will cover this. In these cases we use the Present Perfect Simple, not the Present Perfect Continuous: "I've known him for a long time"
Grammar Blogs are written by Stephen Smith, long standing tutor with years of academic and business experience.