The past perfect continuous and past perfect tenses are often used interchangeably by native English speakers. There is no difference in overall meaning. Take a look at these two sentences. There is no real difference in overall meaning.
I had taught there for four years when the college closed.
or
I had been teaching there for four years when the college closed.
There is no real difference between the two. However, we should use the past perfect continuous tense, also known as the past perfect progressive tense, for some activities that we will discuss as the usages of the past perfect continuous tense.
USAGES
The past perfect continuous tense is used for the action in the past that continued up to a certain time and continued after it.
Example:
They are tired because they had been walking since dawn.
The past perfect continuous tense is used for a repeated action in the past up to a certain point.
Example:
She had been reading the daily dawn for months until she left.
The past perfect continuous tense is used to emphasize the duration of an activity that was continued in the past before another action happened.
Example:
The police had been looking for the culprit for two years before they caught him.
In the above example, the emphasis is on the duration of two years.
Since and For
The word "For" is used for a period of time, whereas the word "Since" is used for a point in time or refers to a time that has begun in the past and still continues.
STRUCTURE
Positive or Affirmative Sentence
She had been cooking for hours.
Formula:
Subject + had + been + Base form of verb + ing + Object
Negative Sentence
She had not been cooking for hours.
Formula:
Subject + had + not + been + Base form of verb + ing + Object
Question or Interrogative Sentence
Had she been cooking for hours?
Formula:
Had + Subject + been + Base form of verb + ing + Object
Negative Questions
Hadn't she been cooking for hours?
Had she not been cooking for hours?
Formula:
Hadn't + Subject + been + Base form of the verb + ing + Object
Had + Subject + not +been + Base form of the verb + ing + Object
The negative interrogative sentences can be made in two ways. If the word "not" is contracted with the auxiliary verb, then it comes before the subject, and if it is not contracted, then the word "not" comes after the subject to make a negative interrogative sentence. In the first sentence, the word "not" has been contracted with the auxiliary verb, while in the second sentence, it has been used in expanded form, and that's why it has been put after the subject of the sentence.
RECOGNITION IN URDU
Examples
Recognition in Urdu is very important. It helps a lot in translation. If you don't know the tense of a sentence, you will be unable to translate it.