The answer, after seven years of extensive research and development, was yes.

The film, because of its extensive research, took almost one and a half years to complete.

In turn, this led to his extensive research on the subject.

It was still going to be necessary to do some hard, extensive research.

Today, there are still extensive research and development efforts around the world in this field.

He also carried out extensive research into the history of economic thought.

We have done extensive research into what the risks are.

But despite extensive research no portrait of him can be found.

However, despite extensive research, no firm record of him has been produced.

Extensive research and evaluation must take place in order to create successful open education systems.