The phrase "are probably lost" is correct and usable in written English.
It can be used when expressing uncertainty about the status of something, suggesting that it is likely no longer available or missing.
Example: "The documents we sent last week are probably lost in the mail."
Alternatives: "are likely missing" or "may be gone".
If all the kids are on the same page in the same book, half of them are probably bored and the other half are probably lost.
Most of the comments uttered at Harvard after the appointment of its new president, Dr. Drew Gilpin Faust, are probably lost to history.
By Lizzie Widdicombe Most of the comments uttered at Harvard after the appointment of its new president, Dr. Drew Gilpin Faust, are probably lost to history.
Once you start down that road, once you begin to think that David Mulford matters more than Bob Solow, or to prefer hobnobbing with the Ruritanian finance minister to talking theory with Avinash Dixit, you are probably lost to research.
Two years since the destruction along Japan's northeast coast, some communities in Fukushima are just starting to come to terms with a sobering realization: their old homes are probably lost forever, and they must start anew elsewhere.
While the fine points of processor names are probably lost on most Mac buyers, Y-series chips are lower power in performance and energy consumption than their U-series siblings.
Now that the getting here has got even harder, many businesses shipping goods into the city are probably losing money.
In the short term, that is not happening and we are probably losing some good young people who might otherwise enter science.
However, if you are a landlord you are probably losing real money every single month and you don't even know it.
If you cannot easily tap it with your fattest finger, you are probably losing much of the value of your effort.
If so, then you are probably losing concentration near the end.
