There are, however, challenges.

One of the challenges to build an interactive digital textbook from the ground up is that is takes a great deal of manpower

They tend to be slow in confronting new challenges.

A new study challenges that belief, questioning whether brains really can be distinguished by gender.

Such children believe challenges are energizing rather than intimidating; they offer opportunities to learn.

These challenges are real, and society urgently needs to address them.

They avoid challenges because challenges make mistakes more likely.

This might be a small change to the way we view work and the office, but the researchers argue that it challenges a widespread characteristic of the economy: work organized by clock time.

Understandably, there are concerns about what this means for public finances given the associated health and pension challenges.

Today we face seeming challenges in energy, the environment, health care.

In the second paragraph, the author challenges the view that the collapse of rain forests is caused by direct human interference.

Many people are seriously concerned by this - and the company is likely to face challenges in other courts around the world.

What is one of the challenges facing the American economy

They dare to take up challenges.

It has encountered increasingly tougher challenges.

In particular, Arum and Roksa found, college students were not developing the critical thinking, analytic reasoning and other higher-level skills that are necessary to thrive in today's knowledge-based economy and to lead our nation in a time of complex c

Macy's reported its sales plunged 5.2% in November and December at stores open more than a year, a disappointing holiday season performance that capped a difficult year for a department store chain facing wide—ranging challenges.

Or do they face more challenges than any previous generation?

Smart basketball players or skilled musicians need to pay close attention to the demands of high performance, to the challenges to be overcome.

The studies also ran up against many methodological challenges, the biggest of which centered on the old statistical saying, "Correlation does not equal causation."

The trouble is, for many of the researchers who'd like to design systems to address these challenges, massive datasets for experimentation just don't exist—at least, not in formats that are accessible to academic researchers.

They're open to the tactical possibilities and the musical challenges precisely because they're freed, through skill, from the need to pay attention to the low-level details of how to play.

To make matters worse, these schools are ill-equipped to graduate these students — young adults who face specific challenges and obstacles.