【正确答案】 C

【答案解析】[听力原文]
The coastal area of North Africa, is almost as pleasant as Southern California, with hot, dry summers, and consistently heavy rains in winter. The forested mountains of Morocco and Algeria have a heavy winter snowfall, and excellent skiing grounds. Temperatures in the coastland"s higher altitudes fall below freezing on winter nights. In the south of the mountains and plateaus the true desert begins. It is not a continuous sea of land; some parts are great stretches of picturesque dunes, but others are rim rock and gravel, not at all flat, and one may travel for days and see scarcely any sand. Rains fall rarely, though then in such large closes that bivouac commanders should take care not to make camp in a ravine. Winter nights are bitterly cold.

A、 The cold of winter nights settles to the lowest part of the plains.
B、 The ravines are rocky and therefore unsuitable for camping.
C、 Sudden rain floods could drown the traveler.
D、 Morning dew settles into the ravines, making them wet and uncomfortable.