()是无色、易挥发、有刺激气味的液体,质量分数达到98%以上时产生发烟现象。
A.硫酸
B.盐酸
C.硝酸
D.氢氟酸
参考答案:C
A business peak is present when:()
A. most businesses are operating at below level and real GDP is decreasing rapidly.
B. most businesses are operating at capacity level and real GDP is decreasing rapidly.
C. most businesses are operating at capacity level and real GDP is growing rapidly.
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