It’s subjective, but I’d say false. If you’re giving a presentation, especially without notes, and you lose your train of thought, saying nothing and stopping mid sentence will be very awkward and almost certainly cause you to lose points. If it were me in that situation, I’d take a second to compose myself and then continue talking about whatever you were just saying before you lost your train of thought. Hopefully this would jog your memory so you would remember where you were and no one will notice anything was wrong