Which of the following sentence is the correct example of "past perfect continuous tense"?

Which of the following sentence is the correct example of "past perfect continuous tense"? Correct Answer At that time Shama had been writting a novel for two months

Related Questions

Rewrite the following sentence using the correct tense in simple past or past perfect of the verbs givenin the brackets:

I (play) sitar when a young lady (come) and (stand) near me. She (listen) to the music for a while and then (ask) me what raga I (play).
Identify the sentence with Past Perfect Continuous tense.