环境空气质量一级标准总悬浮物年平均为每立方米0.8mg。( )
参考答案：对
With the help of the computer, information can ____ every corner of the world swiftly. [ ]
A. get
B. reach
C. arrive
D. return
1μg视黄醇当量（RE）相当于β-胡萝卜素的μg数是（）
A.1
B.3
C.6
D.12
E.18
