电梯井的井壁除开设电梯门洞和通气孔洞外，不应开设其它洞口。电梯门可采用栅栏门。（）
参考答案：错
The price of the houses in this district_________from 5% to 7% in the past two months.
A．has fallen
B．has been fallen
C．was fallen
D．was falling
气瓶操作中，氧气与乙炔瓶的距离为多远？
