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:
How long has the deferred interested been acquiring?
The globalization of this bank has been going on for three years.
How long have your net assets been dwindling?
Positive Form:
Subject + have + been + 'ing' form of verb + (object(s)) + since / for + time expression
I've been writing a promissory note to pay a definite sum of money to the payee since two this afternoon.
Negative Form:
Subject + have + not + been + 'ing' form of verb + (object(s)) + since / for + time expression
The client hasn't been willing to discuss earnest money all week.
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 dealing in stock for over thirty years. That's why I'm such a success today.
We have been working overtime for the past week so your house appraisal is finally complete.
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:
How long has it taken the loan officer to review your letter of credit?
Our bank has used this warehouse for three years.
Example of Present Perfect Continuous:
She hasn't been maintaining the accounts on behalf of the shareholders.
The tech told us that the convertibility upgrades have been ongoing since last spring.
When emphasizing the duration of the current action, use the present perfect continuous.
Example:
We've been discussing who is to be held responsible for this for an hour.
Real estate has been plunging steadily for the last year.
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:
The cash cow product has done well considering the economy.
I've finally identified a cash cow product.