But useful observations are also being made by the naked eye.

The trick relies on the following simple, but very useful mathematical observation.

"Data," Riker said, "were you able to make any other useful observations about this ship or the energy field?"

That's a useful observation, but he takes it too far.

There hasn't really been that much useful observation either, Laria said caustically.

And even if there were not, Archie would still be able to make useful observations.

These features, however, were seen from a low angle, hindering useful observation.

By the 1930s, the smoke and sky-glow of the city had made it impossible to conduct useful observations in Rome.

I would like to thank all those who contributed to the completion of this report with useful observations, proposals and amendments.

However that is a useful observation on the levelling out of the playing field re pensions, over time.