The phrase "are now difficult to" is correct and usable in written English.
It can be used when describing a current state of something that has become challenging or hard to do.
Example: "The tasks we once found easy are now difficult to complete due to the new regulations."
Alternatives: "have become hard to" or "are currently challenging to".
The same has started to happen with mobile phones: colour screens and cameras, once found in only the most expensive phones, are now difficult to avoid.
One of the issues being investigated was whether pressure to reduce major crime further had led some precinct commanders and supervisors to reclassify serious crimes into the lesser categories that are now difficult to analyze.
There are also a lot of vaguely phonetic spellings - such as "Koran" and "Mecca" - that bear little relation to the Arabic spelling but entered popular usage many years ago and are now difficult to eradicate.
Mr. Platt has been with the show since its first reading, nearly two years ago, and he has shaped the character, and it has shaped him, in ways that are now difficult to disentangle.
Schmidt says the process could probably be adapted to work with other biomass, such as slurries or powders made from grass or wood, which are now difficult to convert into practical fuels for electricity generation or transportation because of their high cellulose content.
This orientation is especially advisable when further expansive moves in American criminal justice are now difficult to justify.
After 10 Nd2, it was now difficult to attack the White center.
Yet, with hindsight, it is now difficult to listen to them without hearing prophecy.
"It's now difficult to see why we didn't get it," Dr. Sykes said.
But it is now difficult to judge what is considered private," he said.
As a result of these human activities, it is now difficult to clearly guarantee the sustainable future of humankind.
