Sentence examples for a difficulty has been from inspiring English sources

A difficulty has been the relatively poor binding power of the targeted microbubbles, especially in the non-immunogenic form suitable for human use.

A difficulty has been documented in phylogenetic reconstruction of gene families with anciently duplicated genes [ 26], in which saturation of frequently-mutating amino acids leads to erroneous "outgroup topologies".

A second difficulty has been a paucity of realistic trials that use active placebos or compare drugs believed to be disorder specific (according to current diagnostic classifications or theories) with other drugs known to exert some psychoactive effects.

A major difficulty has been to establish differences in the level and period of past exposure, a prerequisite for hypothesis testing.

The puppy had been fed solid food for a couple of weeks without any difficulty, had been healthy from birth, and was the largest puppy of the litter.

A certain amount of difficulty has been removed, and so things can happen with a dreamlike speed.

The reaction to difficulty has been a broader smile, a wider embrace.

Difficulty has been a key part of the Beal story.

The Dawn Wall, with its extraordinary levels of continuous free-climbing difficulty, has been a continuation of that fascination.

Still, the managers' biggest difficulty has been a decline in orders from South Korean buyers, who they said had stopped buying from Kaesong factories for fear the complex might suddenly be closed down for political reasons.

Unfortunately one of their most public representatives during this time of difficulty has been a man whose actions are indefensible.