There are an impressive series of benchmarks to measure progress but no penalties if progress is not made.

"My, that is an impressive series of titles."

Volume one of what should be an impressive series of bass-centric selections.

It is an impressive series of cascades down a 100 m drop.

These past few days have been an impressive and important series of victories for the American people.

An equally impressive series that has been around for a few years has a charming addition.

It is a most impressive series of documents.

Since then, it has made considerable efforts, putting in place an impressive series of modernising reforms.

Rather than abandon their efforts, Romark launched an impressive series of controlled trials.

He has always been a workaholic, holding down an impressive series of jobs throughout college and graduate school, his mother said.