当包含因子k取2时，其相对扩展不确定度为（）
A.6.45
B.0.44
C.7%
D.0.88
E.14%
参考答案：E
Always read the__________on the bottle carefully and take the right amount of medicine.[ ]
A. instructions
B. descriptions
C. introductions
D. explanations
扫气箱着火时应采取怎样措施？
