1.   A rock was loose and he fell with a sharp cry of surprise.

2.   Agit-poppers convinced themselves that rock was archaic and debased, no longer capable of functioning as a medium for radical comment.

3.   Although a rock is a collection of the chemical elements that make it up, those elements are not distributed randomly.

4.   But whereas the Mare basalts are too dense to represent the lunar mantle, the highland rocks are not dense enough.

5.   Closer inspection revealed that the rocks were from an earlier period.

6.   Fresh volcanic rocks are poor conductors of electricity.

7.   Furthermore, ocean-floor rocks are recycled on time scales of tens of millions of years.

8.   Given the atrocious landings and the fact that the rock is extremely treacherous when wet, many climbs are very bold.

9.   Hardly any lunar rocks are younger than three billion years.

10.   Rock was a roly-poly detective who looked like a no-hoper but who always outwitted the opposition with sly brilliance.