| A.the rain is spread out in a year |
| B.the rain falls only in a few weeks |
| C.there is little rain in a year |
| D.it is dry all the year round |
| A.sand piles up gradually |
| B.there is plenty of rain in a year |
| C.the sea has dried up over the years |
| D.pieces of rock get smaller |
| A.too much sand |
| B.more sand than before |
| C.nothing except sand |
| D.something else besides sand |
| A.there is no rainfall throughout the year |
| B.life exists in rough conditions |
| C.all sand dunes are a few feet high |
| D.rocks are worn away only by wind and heat |