Teachers explained that the past perfect progressive indicates a continuous action that had been happening before another past event.

The neurologist explained that the child's symptoms were consistent with progressive infantile poliodystrophy.

The neurologist explained that progressive sclerosing poliodystrophy typically presents in early childhood with refractory seizures and developmental regression.

At the historical society's reenactment, the musicians taught the audience the steps of a progressive longways formation, reviving an old New England line dance.

The neurologist explained that progressive multifocal leukoencephalopathy is a rare but serious complication in immunosuppressed patients.

Teachers often explain present perfect progressives by comparing them to simpler tenses.

We decided to develop a progressive web app to improve offline access and performance for our users.

Our team decided to rewrite the company's mobile site as a progressive web application to improve offline performance and reduce load times.