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:
We have been working overtime for the past week so your house appraisal is finally complete.
How long have your net assets been dwindling?
The agent hasn't been acting on behalf of his clients in their best interest.
Positive Form:
Subject + have + been + 'ing' form of verb + (object(s)) + since / for + time expression
I've been typing a note for all bank workers about the provision of uniforms since nine this morning.
Negative Form:
Subject + have + not + been + 'ing' form of verb + (object(s)) + since / for + time expression
The non-taxable income hasn't improved at all over the last fiscal year.
Question Form:
(Question Word) + have + subject + been + 'ing' form of verb?
How long has the bank customer been calculating his net assets?
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 the appraisal since six this morning. That's why you have it already.
I've been dealing in stock for over thirty years. That's why I'm such a success today.
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:
The committee hasn't used time efficiently to come to a decision.
Mr. Bill has worked in David and Stevenson Warehouse since 2007.
Example of Present Perfect Continuous:
The non-taxable income hasn't improved at all over the last fiscal year.
That company has been using electronic banking for three years with success.
When emphasizing the duration of the current action, use the present perfect continuous.
Example:
They have been calculating the currency convertibility in the meeting.
We've been discussing who is to be held responsible for this for an hour.
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:
We have greatly diversified your portfolio.
The cash cow product has done well considering the economy.