安全设备的设计、制造、安装、使用、检测、维修、改造和报废，应当符合( )。
A．国家标准或者行业标准
B．地方标准
C．国际标准
D．企业标准
参考答案：A
按要求改写下列句子。
1. Have you looked in the classroom? (做肯定回答)
______, I ______.
2. Jenny is at the computer. (就划线部分提问)
______ ______ Jenny?
3. It's a quarter after three. (改为同义句)
It's a ______ ______ ______.
4. His father has been to America. (就划线部分提问)
______ ______ his father ______?
5. She has finished her homework. (改为一般疑问句)
______ she ______ her homework?
下列关于大气叙述正确的是（）.
A.大气是指包围地球的大气圈的整体
B.近地面大气是由干洁空气和水汽两部分组成的
C.干洁空气的主要成分是氧和二氧化碳
D.大气自下而上分为：对流层、平流层、电离层、高层大气
