利用（）说明方位比较直观。
A．测者子午面天球图
B．测者子午面投影图
C．天赤道面平面图
D．测者真地平平面图
参考答案：D
— How did you find him out?
— I ______ his name by chance on the list. [ ]
A. came down
B. came about
C. came up
D. came across
计算题：若煤气含萘塔前为9.6g/m3，塔后为0.6g/m3，煤气流量为5000m3/h，问理论上每小时可产萘多少吨？
