If this happens, it could explain some very intense radio signals in the sky that have long puzzled astronomers.

Figuring out how and why people quit their jobs has long puzzled managers.

As science advances, it finds the true explanations for many questions that have long puzzled men.

But one aspect of this leaping behaviour has long puzzled biologists.

Yet the ability to enjoy music has long puzzled biologists because it does nothing evident to help survival.

European officials dealing with the euro have long puzzled about how to treat these ministates.

I have puzzled over this command long and often.

The small differences in abilities between the sexes have long puzzled researchers.

Scientists have long puzzled over this rather contrived state of affairs.

The precise process of granite formation has long puzzled geologists.