Happening up to This Moment
Present Perfect Continuous
The present perfect continuous places the emphasis on the duration of a current activity. It is used to express either when an action in progress began, or the length of an action in progress. The present perfect continuous is never used with stative verbs.
Example:
I've been researching restaurant management since last June.
They've been defining their target market for six months.
I've been working on my people skills since summer. That's why I'm so very friendly.
Positive Form:
Subject + have + been + 'ing' form of verb + (object(s)) + since / for + time expression
I've been researching restaurant management since last June.
Negative Form:
Subject + have + not + been + 'ing' form of verb + (object(s)) + since / for + time expression
She hasn't been following the front office procedure manual for months.
Question Form:
(Question Word) + have + subject + been + 'ing' form of verb?
For how long has the diabetic patient been avoiding starches?
Examples of What Caused Something
The present perfect continuous is often used to express the action that caused a present result.
Example:
I've been working on my people skills since summer. That's why I'm so very friendly.
I've been at the all you can eat buffet since eight this morning. That's why I'm so over full.
Present Perfect Contrasted with Present Perfect Continuous
The present perfect and present perfect continuous are both used to express the duration of an activity that begins in the past and continues into the present. Either form is used with general activities, although the use of the present perfect continuous can indicate that an activity is about to change. The present perfect continuous describes the duration of a current activity and tends to be used with more specific action verbs.
Example of Present Perfect:
I've created three prototypes for companies in the vending industry.
Jane has focused on food preparation since January.
Example of Present Perfect Continuous:
I've been working on my people skills since summer. That's why I'm so very friendly.
For how long has the diabetic patient been avoiding starches?
When emphasizing the duration of the current action, use the present perfect continuous.
Example:
They've been defining their target market for six months.
They've been including roasted foods on their menu since 1983.
The present perfect continuous conveys the length of an activity, whereas the present perfect can also be used to relate the quantity, or amount finished up to the present moment in time.
Example:
I've bartended in three restaurants with mini-bars.
I've created three prototypes for companies in the vending industry.