Now though, for some unknown reason, the once chatty pieces are returning to their inanimate state.

For some unknown reason, they escaped felling during the centuries when oak was at a premium - maybe their age was revered even then.

But for some unknown reason — the sociopathy of convention — other people get strangely offended when you don't want to join in.

For some unknown reason, the gene reproduced itself many more times than it should have, creating too much of its protein.

You think you've met the love of your life but you suddenly go cold for some unknown reason and never want to see them again.