1.   It was a remarkable discovery, a previously unknown chemical process that Knittle had stumbled on to.

2.   Overnight a panic spiral of previously unknown proportions will develop.

3.   The bombing is being blamed on a previously unknown group of terrorists.

4.   The cause was eventually tracked down to a previously unknown bacterium, given the name Legionella pneumophila.

5.   The essence of research, surely, must be the revelation of previously unknown facts.

6.   The show starred a previously unknown actress called Jennifer Aniston.

7.   This special afternoon sale will put on offer an album of fifty-eight previously unknown drawings by Henry Fuseli.

8.   Her music was previously unknown outside of Asia.

9.   Searching through the miscellanea in the archive, she came across the draft of an unpublished and previously unknown poem by the reclusive writer.