电梯井必须安装可开启的金属防护门，井道内按标准（）。
A.封闭严密
B.严禁放置物品
C.设水平安全网
D.专人看守
参考答案：C
连铸坯硫印检验是利用放大镜观察铸坯中心硫偏析痕迹的方法。
根据I栏的问题在Ⅱ栏中选择正确的答话。
Ⅰ
( )1. What are the boys doing?
( )2. Let's play ping-pong.
( )3. When do you want to go to the movies?
( )4. What are they talking about?
( )5. Do you want to go shopping with me?
Ⅱ
A. Let's make it at six, OK?
B. That sounds fun.
C. They are playing temiis.
D. Sure-, I'd love to.
E. An interesting place.
