present perfect continuous
form
affirmative
- i / you / we / they've (have) been studying in london.
- he / she / it has been studying in london.
negative
- i / you / we / they haven't (have not) been studying in london.
- he / she / it hasn't (has not) been studying in london.
interrogative
- have i / you / we / they been studying in london?
- has he / she / it been studying in london?
short answers
- yes, i / you / we / they have.
- yes, he / she / it has.
- no, i / you / we / they haven't.
- no, he / she / it hasn't.
use
- to describe an action that began in the past and has been in progress up to now, with emphasis on the duration of the action - example: i've been studying in london for three years.
- with how long?, for and since to emphasize the duration of the action - example: how long have you been studying in london? i've been studying in london for three years.
- to emphasize the continuous nature of an action that has a result / consequence in the present - example: she's been working hard, and that's why she's exhausted now.
- to underline that an action has literally just stopped and its results / effects are still visible now - example: it's been raining, and the streets are wet.
for
- to indicate the entire period of time, or total amount of time a situation has been true.
- signal words: 10 minutes, an hour, a day, a week, etc.
since
- to indicate the starting point, or moment when a situation began.
- signal words: 8 p.m., last week, january 1st, 2010, etc.