1.   Electronica is becoming an equal opportunity employer far more quickly than rock did, but history may merely repeat itself.

2.   Rock does double duty as both twins.

3.   Since water reflects radar better than rock does, the signal bounced back would have a distinct look if an ocean lay beneath the ice.

4.   Sports once had the problem rock did.

5.   There is no evidence that it flew, nor does the rock in which it was found bear any imprint of feathers.

6.   Even British rock is doing its bit from abroad.