The phrase "are difficult to clear" is correct and usable in written English.
It can be used when describing something that poses a challenge or obstacle to being resolved or removed.
Example: "The obstacles in the project are difficult to clear, which is causing delays in our timeline."
Alternatives: "are hard to resolve" or "are challenging to remove".
This condition results in viscous secretions that are difficult to clear, leading to decreased mucus clearance of the airways and subsequent airway obstruction, recurrent infections, and airway damage, which progress over time.
Since podocyte deposits are difficult to clear by ERT, contrary to endothelial deposits, this further supports a key role of podocyte injury in FD [ 24].
Furthermore, cystic fibrosis (CF) patients are known to develop progressive cytokine-mediated inflammatory lung disease, with abundant production of thick, tenacious, protease-rich and oxidant-rich purulent airway secretions that are difficult to clear, even with physiotherapy.
That may be difficult to clear with Russia and China, both of which are profiting from arms sales to the impoverished antagonists.
Just as it is difficult to clear the weeds and restore the original rainforest trees, it is challenging to rehabilitate the gut communities of chronically malnourished children.
Fresh produce is hard to find during winter, and long driveways that provide privacy can be difficult to clear after a large snowfall.
Then they explained, sheepishly, that there was a section of the road, just near the airport, that was difficult to clear.
Such a move subjects the bill to hurdles that would be difficult to clear before the Senate's adjournment, scheduled for Sept. 26.
"The conditions are difficult and as a defender it's difficult to clear your lines.
Since children sometimes create a game which is difficult to clear, the stickers include negative emotions.
" It was a difficult pitch, puddles everywhere and it was difficult to clear your lines in the second half.
