I am a English learner from Poland. One thing confuses me often while reading in English. It is the sentence "can never". Does that sentence mean that one will never be/do something 100 percent? Or it means it is possible that one will not do something but it is not 100 percent (can never do this, but also can always do this)?
The meaning of “can never” depends on the context. There is a very similar question like yours that goes into great detail right here.
This means that 'they' are not capable of performing 'X'. They have no legs, so they can never walk. They have no way of earning money, so they can never have expensive things. 'X' is impossible for 'them', so it will never happen.
"Can never" isn't a sentence. The meaning depends on context.
It is not necessarily an expression of certainty.
Indeed, colloquially "can never" means "often can't":
- "I can never understand what he's talking about."
- "I can never find my keys!"
- "I can never find a parking space."
"I can never" often refers to habitual, repetitive experiences.
When talking about the future, we tend to say "I'll never be able to" or "I'm never going to be able to" (though these doesn't express certainty either - just as often, they are an expression of despair: "I'll never be able to finish the essay in time"). So "I can never ride a bike" suggests "I never get the opportunity to ride a bike" (habitual/present), whereas "I'll never be able to ride a bike" is a prediction that I'll never be able to (whether in terms of ability or opportunity).