These have indeed been very challenging times for our Organization.

And this is a very challenging idea. It's a very challenging idea to mainstream media. It's a very challenging idea to anyone who has invested an enormous amount of time and expertise, and who has a lot of energy invested in the notion that he or she knows better than everyone else.

But, for everyone else, particularly small and medium size firms, the credit environment continues to be very challenging.

So, all things considered, China s looming leadership transition is shaping up to be a very challenging period for China and the world.

According to Jean Marie Guehenno, the head of UN peacekeeping operations, any hybrid force must be robust because of the very challenging situation in Darfur.

A bit more challenging, right?

I'm also very hopeful that in the next decades, we will make big strides on reducing that death rate that has been so challenging in this disease.

He commended the leadership of the Secretary General and the High Commissioner and the dedication of their staff to their very challenging mission under increasingly dangerous circumstances.

A bit more challenging, right? (Laughter)

It s an equation with very many known unknowns, but if we do not try at least to mitigate these issues, the known unknowns will continue challenging all partial solutions.

But striking the proper balance is challenging.

That will be particularly challenging for Bernanke.

That is an assumption that needs challenging.

Emerging and challenging issues deriving from implementation

Although safety concerns are paramount right now, the construction of new nuclear plants faces another hurdle they are very expensive. New nuclear power plants have high up front costs (which can be politically challenging), including a very complicated, slow, and fraught planning process.

Finally, Japan s external environment today is more challenging.

However, the situation in Cité Soleil remains challenging.

Two serious problems make reconciliation in Afghanistan particularly challenging.

But success in Cairo might prove even more challenging.

This means that Europe probably faces another challenging year.

The selection of indicators has proven to be challenging.

Women challenging these norms are punished by violent means.

Emerging and challenging issues deriving from implementation and necessary

The year ahead will be challenging and rife with uncertainty.

Everything we do, we believe in challenging the status quo.

You can see the trapezoids are a little challenging there.

Fortunately, such a way immensely challenging but nonetheless feasible exists.

This category is especially useful for solving especially challenging problems.

In this challenging environment, administrative infrastructures have continued to function.

This has been particularly challenging in remote and insecure areas.

America, however, is not alone in challenging Al Jazeera head on.

Aside from clarity, it is important that group goals be challenging.

The Second Great Awakening was challenging women's traditional roles in religion.

Determining an optimal level of accountability for results is also challenging.

Some individuals and entities have filed multiple lawsuits challenging their listing.

In Libya, the transitional authorities are finding it extremely challenging to create a coherent political structure that can unite two very different provinces, Cyrenaica and Tripolitania, which were held together only by the Qaddafi regime s brutality.

Particularly challenging is the need to explain the very high efficiencies that are inferred from some explosions some gamma ray bursts may convert as much as half (or more) of the explosion energy into gamma rays.

Some local journalists and civil society groups are challenging the credibility of some of the results, and the CPC is challenging the outcome of the presidential vote at the INEC.

Opposition leaders do not like the subject, but they avoid challenging it.

Most should be able to grow strongly, despite the challenging global environment.

Of these three imperatives, sustainability may be the most complex and challenging.

It will be challenging, but maybe also healthy for our common future.

The journey from 2011 to now has been challenging, exciting and tedious.

Managing such a large and complex peacekeeping mission was a challenging task.

The Perpetuity Growth Model has several inherent characteristics that make it intellectually challenging.