天然气管道放空前准备工作应包括向（）和村社通报具体情况。
A.用户
B.地方消防部门
C.领站
D.领导
参考答案：B
She_____ her hometown for many years. No one nearly knows her.[ ]
A. has been away from
B. has left
C. had left
图象的分辩率为300象素每英寸，则每平方英寸上分布的象素总数为（）。
A.600
B.900
C.60000
D.90000
