"认为做不到的人不应该打扰正在做的人。"

Simplified Meaning:

When someone believes a task is impossible, they shouldn't stop or distract the person who is actually trying to get it done. Imagine an inventor working on a new machine. If others keep telling them it's a waste of time, they might get discouraged and lose focus. But if they ignore the naysayers and keep working, they might eventually succeed and prove everyone wrong. In history, think of the Wright brothers who invented the airplane. Many people thought flying was a crazy idea. If the Wright brothers had listened to them, they might have given up. But they kept working, and now we have planes flying all over the world. So, if you're trying to achieve something difficult and people say it's impossible, don't let their doubts stop you. Keep pushing forward and show them what can be done. And if you're someone who doubts others, give them space to try. They might just surprise you and achieve great things.