题目内容:
Glasermadehisdiscoveryby( ).
A.studyingpatchesoffertilesoilsinthecentralAmazon B.examiningpotteryleftoverbyancientcivilizations
C.test-burningpatchesoftreesinthecentralAmazon
D.radiocarbon-datingingredientscontainedinforestsoils
参考答案:
答案解析: