[单项选择]

The first man who cooked his food, instead of eating it raw, lived so long ago that we have no idea who he was or where he lived. We do know, however, that 56 thousands of years food was always eaten cold and 57 . Perhaps the cooked food was heated accidentally by a 58 fire or by the melted lava from an erupting 59 . When people first tasted food that had been cooked, they found it tasted better. However, 60 after this discover, cooked food must have remained a rarity 61 man learned how to make and light 62 .
Primitive men who lived in hot regions could depend on the heat of the sun 63 their food. For example, in the desert 64 of the southwestern. United States, the Indians cooked their food by 65 it on a flat 66 in the hot sun. They cooked piece of meat and thin cakes of com meal in this 67 . We surmise that the earliest kitchen 68 was stick 69 which a
A. food
B. a fire
C. himself
D. it