一番よく使われている表現はWe cannot findです。
"We cannot find"は何かを見つけることができないときに使われる表現です。
"We cannot found" は過去形ではありません。"found"は確立することを意味するので、この表現は"We cannot establish (something)."という意味になります。
There are certain documents that, up to this day, we cannot find, search as we may.
We are a continent that is sending USD 2 billion worth of weapons to drought-stricken Ethiopia and we cannot find a couple of helicopters to send urgently to save people drowning in Mozambique.
Everyone knows that we cannot find a solution within a week.
Vera, I admire your spirit, but we cannot find the next Horseman without Joshua's vision.
Like I said, we are ready to authorize that payment to you, but we cannot find a Manford listed.
We are trying to authorize payment of your paycheck to you. It's from a Mr. Manford via Brent Wilts, but we cannot find a Manford in our system.
At the same time, it is also clear that we cannot find a silver bullet and there is no silver bullet.
Why we cannot find the will to transfer a proportion of that money to secure peace on our continent by rebuilding civil society in former Yugoslavia?
We cannot find answers within orthodox Islamic thinking.
We cannot found a business with no money at all in our pockets.
The Founding Fathers of the United States know that they could not found a democratic country on a theocracy.
We cannot found this institution unless we get enough signatures.
Is there any kind of organization or program we cannot found in this city?
Is there a restaurant in the state this man cannot found?
She has founded several non-profit organizations.
You cannot found a new city in the desert with no resources.
The group could not found any more institutions to help their citizens.