| 1 | I've never heard of such a strange thing before. | |
| 2 | And it came in on time, which is pretty much unheard of. | |
| 3 | While the boy's find was rare, it's not unheard of. | |
| 4 | I imagine extraordinary intrigues and unheard of wines and passions. | |
| 5 | Thus, the "Cambrian Explosion" is a fairly unheard-of term outside the scientific community. |