Tenses Questions
The past perfect continuous tense is used to describe an ongoing action that started in the past and continued up until another point in the past. It is formed by using "had been" + present participle (-ing form of the verb).
Example: She had been studying for three hours before she took a break.
On the other hand, the present continuous tense is used to describe an ongoing action happening at the present moment. It is formed by using "am/is/are" + present participle (-ing form of the verb).
Example: He is studying for his exam right now.
In summary, the main difference between the past perfect continuous and present continuous tenses is that the past perfect continuous refers to an ongoing action in the past, while the present continuous refers to an ongoing action in the present.