Mathers prefers the flat rate tax probably because______.
A. it is fair and easy to figure out
B. he pays heavy taxes
C. it is more applicable than the progressive rate for him
D. all of the above
According to Peter Senior, which of the following is true？
Art should be encouraged in British hospitals.
B. Art is losing its audience in modern society.
C. Art galleries should be changed into hospitals.
D. Art should be spread to the patients in hospitals.
沙尘在起沙、输送、降落的过程中沙尘粒径谱是不断变化的。()
扩散公式中烟流的高度是烟源的有效高度，也就是烟囱的实际高度。()
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