31-35简答题（NO MORE THAN 3 WORDS）:
31.In what form did the Aztec pay their tribute to emporer?
（goods particularly crops ）
32. When the historian become aware of the rapid population growth among Aztec?（200 years ago ）
（参考原文：In a period from 1300 to 1500, one of the major population explosion in the history, increasing from about 150000 to around a million. That was 200 years ago before the Spanish conquest.）
33. Which areas besides hill sides did the Azetecs bring into cultivation?
（参考原文：Wet land for cultivation, for example marshes）
34. where did the only archaeological evidence come from?
（Casemates/Capital Castle）/ (by own excavation)
(not sure 如果没把握了就填 the castle)
35. Apart from home what kinds of buildings did Cuexcomate have?
(storehouses and temples )
The speaker mentioned several factors suggest that Atec farmer were more than simple peasants?
the payment of high tributes
the existent of a marketa systerm
imports from other country
the exchanging of craft googds
the export of highly decoration pottery
the exsistent of pottery (原文用：import )
Rich colored bowls are in the house of both families and 39.（common residence）
Same in the case of metal
Only exception on this 40. （precious stones）which we can probably ignore