门窗按使用材料分类有那些？
参考答案：
木门窗、钢门窗、铝合金门窗、塑钢门窗、玻璃钢门窗、镀锌彩板门窗等。
乙状结肠扭转时钡灌肠X线检查可见扭转部位钡剂受阻，呈现
A．“中断”
B．“杯口”
C．“鸟嘴”
D．“线状”
E．“倒3征”
--- Journalists have to work very quickly in order to_______.
--- I know. I like that. It’s very challenging.
A．meet their deadlines
B．earn a high salary
C．avoid being fired
D．make both ends meet
