"Robots don't lose their concentration and are happy to do jobs that are repetitive and difficult, allowing humans to do something else that might be more exciting and profitable," Dr. Harvey said.
But the Democrats' leaders have made that more difficult — allowing the Republicans to maneuver them into the embarrassing position of blocking a vote on a counterproposal that they feared too many Democrats might vote for.
Virtual environments difficult allow or promote certain forms of teaching and learning (Onrubia, 2005).
This made ground surveillance of the Ho Chi Minh Trail much more difficult, allowing North Vietnam to move supplies and develop new branches of the trail.
However, any study which attempted to record immediate reactions would be ethically difficult (allowing potentially dangerous antisocial behaviour), and either require an experimental (automatically limiting generalizability) or observational design.
Although "The Man Who Loved Children" is probably too difficult (difficult to stomach, difficult to allow into your heart) to gain a mass following, it's certainly less difficult than other novels common to college syllabuses, and it's the kind of book that, if it is for you, is really for you.
"That's going to be a very difficult situation," allowed Peter F. Vallone, the Council speaker.
The far places should be left to a few skeleton-crew outposts, and the difficult environment allowed to revert to wilderness, the experts maintained.
Casualty figures on cliff-fringed "Bloody" Omaha, where difficult terrain allowed German machine gun fire to tear into troops, were higher than on any other beach.
Her knack for drawing out the best in even the most difficult people allowed her to say something good about everyone.
