第3题: [单项选择]世界上最早的天文学著作是( )。 A. 《甘石经文》 B. 《甘石星经》 C. 《水经注》 D. 《齐民要术》 参考答案:B 答案解析:[解析] 战国时期，甘德写有《天文星占》，石申写有《天文》，后人把这两部著作合为一部称《甘石星经》，是我国也是世界上最早的一部天文学著作。因此，此题正确答案为B。
第8题: [名词解释]ethnic dialect 参考答案:An ethnic dialect is a social dialect of a language，often cutting across regional differences. It is spoken mainly by a less privileged population that has experienced some form of social isolation， such as racial discrimination or segregation.
