at length

at length  {adv. phr.}
1. In detail; fully.
You must study the subject at length to understand it.
The teacher explained the new lesson at length to the students.
2. In the end; at last; finally.
The movie became more and more exciting, until at length people were sitting on the edge of their chairs.
Categories: study {adv. phr.}

'at length' on video