Sentence examples for hard to known from inspiring English sources

But the rate of DNA change has probably not been constant throughout evolution, especially in its early days, making it hard to known if gene-based trees like Dr. Woese's do indeed extend to the last common ancestor as they seem to on paper.

When at one point Calder slowly and carefully removes layer after layer of hand-sewn costumes from one clown figure until he arrives at what looks like a skeleton, it's hard to known whether you're seeing a circus or a medieval morality play.

Very hard to know.

Hard to know.

He's hard to know.

It is hard to know.

JEFFREY TOOBIN: Hard to know.

It was hard to know.

That's hard to know.

Also very hard to know.

It is hard to know for sure.