阿拔斯王朝是伊斯兰的第几大王朝（）
A、一
B、二
C、三
D、四
参考答案：B
The boss told us that his company __________ in 1999.[ ]
A. establishes
B. established
C. has established
D. was established
地籍细部测量的核心工作是( )。
A．确定图斑面积 B．测定界址线方位C．测定界址点 D．勘丈界线
