In these early days, flying was a dangerous endeavour; accidents and deaths were common.

This was a dangerous endeavor, as the Marines carried loaded weapons.

What a shame, he thought, that so much genius and creativity was spent on such a dangerous endeavor.

It will be a long and dangerous endeavor.

Needless to say it is a dangerous endeavor that requires stamina and experience.

However, the knowledge that he was involved with similar-minded men in a difficult and potentially very dangerous endeavor heightened his natural sense of responsibility.

There is not a trace of the craziness in him that some conclude must drive a man to such dangerous endeavors.

"It was always a very dangerous endeavor," he said.

It can however be a dangerous endeavor and should not be attempted unless one is extremely cautious.

The high-speed machines they drive are continually in a battle for new records, an often dangerous and grueling endeavor.