建筑外门窗水密性等级中下列哪个不属于三级的指标值（）
A、350帕
B、300帕
C、280帕
D、250帕
参考答案：A
—You' re too tired, and you should stop _______ a rest.
—I know, but I can't stop ___________. I need money. [ ]
A. to have ; works
B. having ; to work
C. to have; working
D. having ; working
实验室用铁与盐酸反应，若制得气体体积为11.2L（标准状况下），则该气体的分子数为
A． 6.02×1023
B．3.01×1023
C．2
D．1
