| English | Russian |
| be always looking for a flaw in a theory | постоянно искать недостатки в теории (and the only way to find a flaw is to test it; CNN Alex_Odeychuk) |
| perturbation theory in the continuous spectrum | теория возмущений в непрерывном спектре (jagr6880) |
| possible in theory | теоретически возможный (New York Times Alex_Odeychuk) |