https://www.youtube.com/watch?v=88L7ErhfLFQ
I had been waiting there for two hours before she finally arrived.
She had only been studying English for two years before she got
the job.
note :
* When you are using a verb tense with more than one part
such as Past Perfect Continuous (had been studying),
adverbs often come between the first part and the
second part : had only been studying